# 6. Items to avoid This section lists products and treatments that *seem* inexpensive and effective at first glance. Yet once you look at the original research, their benefits are practically nonexistent — or even negative. They’re arranged based on two factors: how much money people spend on them and how strong the supporting evidence actually is. The items near the top of the list are the ones you should stop using first. ### 1. Don’t take multivitamins for longevity or heart protection - Cost: They cost roughly 0.5 to 2 yuan per day, or 200 to 700 yuan per year. Taking them requires almost no time — just one pill a day. Over time, they can create a sense of dependency, making it feel like something is missing if you skip a day. - In plain terms: Over 14000 male doctors took multivitamins for eleven years. The number of serious heart and vascular problems, as well as deaths, was virtually identical between those who took them and those who didn’t. When nine separate trials involving more than 50000 participants were pooled together, there was no measurable effect on mortality at all. Skipping them saves you between 200 and 700 yuan each year. This does not apply to people who have been medically diagnosed with specific nutrient deficiencies, nor to pregnant women needing folic acid. - Benefit: The PHS II trial enrolled 14641 male doctors and followed them for a median period of 11.2 years (some longer, some shorter). The rate of major cardiovascular events was identical between the groups; the hazard ratio was 1.01 (95% CI 0.91–1.10), meaning no real difference. Similarly, overall mortality showed no difference, with a hazard ratio of 0.94 (95% CI 0.88–1.02). The USPSTF evaluated nine randomized controlled trials with 51550 participants and concluded there is insufficient evidence to support any link between multivitamins and reduced mortality; it assigned a Grade I rating. The perception that they are worthwhile stems largely from the idea of “one pill covering all nutrients” and their extremely low cost. - Evidence grade: A - Sources:Sesso HD et al. (2012). Multivitamins in the prevention of cardiovascular disease in men: the Physicians' Health Study II randomized controlled trial. JAMA. ；US Preventive Services Task Force (2022). Vitamin, Mineral, and Multivitamin Supplementation to Prevent Cardiovascular Disease and Cancer. JAMA. ；Gaziano JM 等 (2012). Multivitamins in the Prevention of Cancer in Men. JAMA. （备注里那项癌症结果） - Notes: A point of debate: among the same group of male doctors, cancer rates were examined as well. Those taking multivitamins showed an 8% lower incidence of cancer (95% CI 0.86–0.998, P=0.04), which just barely crosses the threshold for statistical significance. Cancer-related mortality was also 12% lower (95% CI 0.77–1.01), but this range includes 1, so it may well be a random fluctuation. Any such benefit appears very small and applies only to male doctors. It does not apply to individuals with diagnosed nutrient deficiencies, pregnant women, or those with highly unbalanced diets who require targeted supplementation as advised by medical professionals. ### 2. Don’t take regular fish oil capsules to prevent heart disease - Cost: It costs roughly 1 to 3 yuan per day, or 400 to 1000 yuan per year. Taking it requires no extra time at all. - In plain terms: Two large trials enrolled 26000 and 15000 people with diabetes respectively. For those who took 1 gram of fish oil daily, the rates of major cardiovascular events and death were identical to those who did not take it. The fact that eating fish is beneficial does not mean fish oil capsules are equally helpful. Skipping them saves you 400 to 1000 yuan each year. - Benefit: The VITAL trial included 25871 participants who took 1 gram of fish oil daily for a median follow-up of 5.3 years. No difference emerged between groups in terms of major cardiovascular events or death. The hazard ratio for major cardiovascular events was 0.92 (a hazard ratio of 1 indicates no difference); its 95% confidence interval of 0.80–1.06 also confirms no meaningful difference. The hazard ratio for all-cause death was 1.02 (0.90–1.15). The ASCEND trial involved 15480 diabetic patients who took the same daily dose for an average of 7.4 years, and again no significant differences were observed: the relative risk for serious vascular events was 0.97 (0.87–1.08) and for all-cause death it was 0.95 (0.86–1.05). The perception that fish oil is worthwhile stems from many people mistakenly equating the health benefits of eating fish with those of fish oil capsules. - Evidence grade: A - Sources:Manson JE et al. (2019). Marine n-3 Fatty Acids and Prevention of Cardiovascular Disease and Cancer. NEJM. ；ASCEND Study Collaborative Group (2018). Effects of n-3 Fatty Acid Supplements in Diabetes Mellitus. NEJM. ；Bhatt DL 等 (2019). Cardiovascular Risk Reduction with Icosapent Ethyl for Hypertriglyceridemia. New England Journal of Medicine. （备注里那项高纯度处方鱼油试验） - Notes: Controversy: One trial did produce positive results. The REDUCE-IT trial enrolled 8179 participants with existing cardiovascular disease or diabetes, who were already taking statins and had elevated triglyceride levels (135–499 mg/dL). They took 4 grams of prescription-grade pure EPA daily, which lowered their risk of adverse events to 17.2% from 22.0%. This represents roughly a quarter reduction in risk (hazard ratio 0.75, 0.68–0.83). However, this was a high-dose prescription medication given to high-risk patients, not ordinary over-the-counter fish oil supplements. Eating fish itself is not covered by these findings. ### 3. Don’t give vitamin D supplements to people who already have enough - Cost: Roughly 0.2 to 0.5 yuan per day, or 100 to 200 yuan per year. That’s not much money, but the real cost is the false sense of security it gives — the belief that you’ve already taken preventive steps. - In plain terms: Two large trials looked at this issue. One involved 26000 participants who took supplements for five years; the other included 21000 older adults on supplements for the same period. For people who already had adequate vitamin D levels, there was no change in cancer rates, cardiovascular problems, or overall mortality — the death rates were 5.3% versus 5.1% respectively. This does not apply to people who truly lack vitamin D, those with osteoporosis, or anyone who rarely gets sunlight; they should follow their doctor’s advice. - Benefit: The VITAL trial followed 25871 participants who took 2000 IU of vitamin D daily for 5.3 years on average. No difference emerged in cancer rates, cardiovascular issues, or overall mortality. For cancers likely to spread, the hazard ratio was 0.96 (a range of 0.88–1.06), meaning no real effect. Similar results appeared for major cardiovascular events and overall death rates. The absolute value of this effect is 0.93. The D-Health trial involved 21315 Australians over 60; they received 60000 IU monthly for five years, yet saw no meaningful change in mortality or other outcomes. The apparent benefit often stems from studies that only observe low vitamin D levels without intervention, mistakenly concluding that supplementation helps. - Evidence grade: A - Sources:Manson JE et al. (2019). Vitamin D Supplements and Prevention of Cancer and Cardiovascular Disease. NEJM. ；Neale RE et al. (2022). The D-Health Trial: a randomised controlled trial of the effect of vitamin D on mortality. Lancet Diabetes Endocrinol. - Notes: These trials specifically excluded people with proven vitamin D deficiency, so their findings apply only to those already getting enough. Individuals who truly lack vitamin D, have osteoporosis, rarely get sunlight, or are infants still need proper medical guidance. This analysis focused solely on overall mortality, cancer, and cardiovascular health; other effects were not examined. ### 4. Don’t take antioxidant supplements to prevent cancer (beta-carotene, vitamin E, vitamin A) - Cost: Roughly 0.5 to 2 yuan per day. For smokers, the real cost is a higher risk of lung cancer. - In plain terms: This isn’t just ineffective — it’s actually harmful. A review of 78 randomized controlled trials involving nearly 300000 people found that those taking antioxidant supplements had a slightly higher overall mortality rate. Two large trials focused on smokers showed that beta-carotene raised the likelihood of developing lung cancer by 18% to 28% and increased death rates by 8% to 17%. Smokers and people exposed to asbestos should absolutely avoid these supplements. - Benefit: Cochrane analyzed 78 randomized controlled trials with 296707 participants. Overall, those taking antioxidant supplements had a relative risk of death of 1.02 (a value of 1 means no difference; the 95% confidence interval was 0.98–1.05). When only higher-quality trials were considered, the relative risk rose to 1.04 (1.01–1.07). Specifically, beta-carotene raised the risk to 1.05 (1.01–1.09) and vitamin E to 1.03 (1.00–1.05). The ATBC trial followed 29133 male smokers who took 20 mg of beta-carotene daily; it found a 18% higher rate of lung cancer (range 3%–36%) and an 8% higher overall mortality rate (range 1%–16%). The CARET trial included 18314 smokers and asbestos-exposed individuals; it showed a 28% higher risk of lung cancer (relative risk 1.28, 1.04–1.57) and a 17% higher risk of all-cause death (relative risk 1.17, 1.03–1.33). The perception that these supplements are beneficial stems from the flawed logic that antioxidants prevent aging, which in turn prevents cancer — each step of this chain seems intuitive at first glance. - Evidence grade: A - Sources:Bjelakovic G et al. (2012). Antioxidant supplements for prevention of mortality in healthy participants and patients with various diseases. Cochrane Database Syst Rev. ；The Alpha-Tocopherol, Beta Carotene Cancer Prevention Study Group (1994). The effect of vitamin E and beta carotene on the incidence of lung cancer and other cancers in male smokers. NEJM. ；Omenn GS et al. (1996). Effects of a combination of beta carotene and vitamin A on lung cancer and cardiovascular disease. NEJM. - Notes: The US Preventive Services Task Force, the official US body that evaluates preventive measures, assigned a grade D to beta-carotene and vitamin E in 2022, meaning these supplements are not recommended. Smokers and asbestos-exposed individuals have already suffered harm from their use. Antioxidants naturally present in fruits and vegetables are not covered by this recommendation, so they can still be consumed as normal. ### 5. Don’t expect glucosamine/chondroitin to treat knee osteoarthritis - Cost: Roughly 2–5 RMB per day, or 700–1800 RMB per year. - In plain terms: The GAIT trial involved 1583 participants with knee osteoarthritis who took the supplements for 24 weeks. In the placebo group, 60.1% reported reduced pain. Glucosamine only improved this rate by 3.9 percentage points (P=0.30), while chondroitin added 5.3 percentage points (P=0.17). Taking both together yielded a 6.5 percentage point improvement (P=0.09). All these differences are so small they could easily be due to chance. Spending 700–1800 RMB yearly essentially buys you the same placebo effect seen in 60% of participants. - Benefit: As noted above, glucosamine and chondroitin showed minimal benefits compared to placebo. The real active drug in the trial, celecoxib, produced a 10.0 percentage point improvement (P=0.008). The perceived value of glucosamine/chondroitin stems from their “cartilage-repair” reputation and the fact that placebo alone helped 60% of patients. - Evidence grade: A - Sources:Clegg DO et al. (2006). Glucosamine, chondroitin sulfate, and the two in combination for painful knee osteoarthritis. NEJM. - Notes: Controversy: Among participants with severe baseline pain, those taking both supplements saw a 79.2% pain-reduction rate versus 54.3% in the placebo group (P=0.002). However, researchers note this finding was derived post-hoc and should be viewed as a preliminary clue rather than a definitive conclusion. Proven treatments for knee osteoarthritis include weight loss and muscle-strengthening exercises — see Section 2. ### 6. Don’t rely on vitamin C to prevent colds - Cost: Each effervescent tablet costs roughly 1–2 yuan; annual expense ranges from 300 to 700 yuan. - In plain terms: A combined analysis of 29 controlled trials involving 11306 participants shows that daily vitamin C intake hardly reduces the likelihood of catching a cold. Taking it after symptoms appear also yields inconsistent results. It can shorten the duration of a cold by about 8%, which equals roughly half a day of reduced discomfort. The absolute number of people who benefit from this effect is 500. Whether this half-day of relief is worth spending several hundred yuan per year is a personal calculation. Marathon runners and soldiers stationed in cold climates form the exception: among them, daily vitamin C intake cuts cold incidence roughly in half. - Benefit: Cochrane’s pooled analysis of 29 trials with 11306 participants indicates that regular vitamin C consumption does not meaningfully lower overall cold incidence; the risk ratio is 0.97 (95% CI 0.94–1.00). For trials where vitamin C was taken after cold onset, results varied widely — some showed benefit while others did not. Among participants who took it regularly, the average cold duration decreased by 8% in adults (95% CI 3%–12%) and 14% in children (7%–21%). Marathon runners, skiers, and soldiers in cold environments again represent the exception: five trials with 598 participants demonstrated that vitamin C intake reduced cold incidence by half (RR 0.48; 95% CI 0.35–0.64). Its perceived value stems largely from its low cost, pleasant taste, and the long-standing belief that vitamin C prevents colds. - Evidence grade: A - Sources:Hemilä H, Chalker E (2013). Vitamin C for preventing and treating the common cold. Cochrane Database Syst Rev. - Notes: Controversy: The same review confirms that regular vitamin C intake does shorten cold duration — by 8% in adults (3%–12%) and 14% in children (7%–21%), equating to roughly half a day of reduced illness per cold episode. Marathon runners, skiers, and soldiers in cold climates remain the exception; five trials involving 598 subjects show a 50% reduction in cold incidence (RR 0.48; 95% CI 0.35–0.64). The vast majority of people do not fall into these categories. ### 7. Don’t get a whole-body PET-CT or tumor marker panel if you have no symptoms - Cost: A whole-body PET-CT costs roughly $7000–$10000 per scan and exposes you to ionizing radiation. Tumor marker panels cost a few hundred dollars. The real cost comes later: when an “abnormality” is found — usually a false positive — follow-up tests, biopsies, and surgeries add up both financially and physically. - In plain terms: Screening completely healthy people most often yields false alarms. In one study, 86% of 1192 symptom-free individuals had at least one “abnormality” on a whole-body CT; 37% were called back for further tests, yet the vast majority of findings turned out to be benign. In large trials of ovarian cancer markers, the screened group actually had a slightly higher death rate. In some studies, 0.2%–3.25% of people underwent unnecessary surgery simply because of false positives. - Benefit: The USPSTF, which evaluates preventive measures in the U.S., assigned a D rating to CA-125 testing and ultrasound screening for ovarian cancer in asymptomatic women — meaning it does not recommend them. This decision was based on the PLCO trial, which showed a 0.34% death rate from ovarian cancer in the screened group versus 0.29% in the usual care group (RR 1.18; 95% CI 0.82–1.71). No real benefit was demonstrated. The proportion of people undergoing needless surgery due to false positives ranged from 0.2%–3.25%, and only up to 15% of those developed serious complications. Another study found that 86% of 1192 symptom-free people showed at least one “abnormality” on whole-body CT; 37% were advised to undergo further tests. Most of these findings were benign. The idea that “early detection saves lives” sounds logical, but the data do not support it here. - Evidence grade: A - Sources:US Preventive Services Task Force (2018). Screening for Ovarian Cancer: US Preventive Services Task Force Recommendation Statement. JAMA（同一份建议另有 USPSTF 官方页）. 、；Furtado CD et al. (2005). Whole-body CT screening: spectrum of findings and recommendations in 1192 patients. Radiology. - Notes: The tumor marker portion of this recommendation is backed by randomized controlled trials. In contrast, the evidence for whole-body CT and PET-CT screening relies mainly on observational follow-ups without proper control groups, so it is rated as B. Other proven screening methods — such as those for colorectal cancer, cervical cancer, breast cancer, and low-dose chest CT for high-risk individuals — are discussed in Section 1. This recommendation does not apply to people already showing symptoms or those already diagnosed with cancer; for them, PET-CT is a diagnostic tool, not a screening measure. ### 8. Don’t expect fitness trackers or smartwatches to help you lose weight - Cost: Devices cost between 200 and 2000 RMB. Plus, you have to constantly pay attention to the data they display every day. - In plain terms: 471 overweight adults followed the same diet and exercise plans. The group wearing fitness trackers lost just 3.5 kilograms over two years, while the group without devices actually lost 5.9 kilograms. Trackers do not aid weight loss; regular exercise itself is what makes the difference. - Benefit: The IDEA trial involved 471 overweight or obese adults and lasted 24 months. All participants followed identical diet and exercise regimens; the only difference was whether they wore wearable devices. Those wearing devices lost 3.5 kilograms (95% CI 2.6–4.5). The other group lost 5.9 kilograms (95% CI 5.0–6.8), a difference of 2.4 kilograms (95% CI 1.0–3.7; P=0.002). The devices seem cost-effective only because the idea that “quantification enables management” sounds logical, and they only require a one-time purchase. - Evidence grade: B - Sources:Jakicic JM et al. (2016). Effect of Wearable Technology Combined With a Lifestyle Intervention on Long-term Weight Loss: The IDEA Randomized Clinical Trial. JAMA. - Notes: This is based on just one trial using early 2010s wrist-worn devices, so we cannot claim that “all wearable devices are useless.” Exercise itself remains effective, as discussed in Section 2. This point simply emphasizes that buying such devices is not a necessary expense if your goal is weight loss. ### 9. Don’t pay a premium for organic food just to be “healthier” - Cost: Typically 1 to 3 times the price of regular versions of the same foods. - In plain terms: When we combine 17 studies done on humans with 223 studies analyzing food composition, there’s no solid evidence that organic food is significantly more nutritious. Only 3 of those studies actually looked at health outcomes after people ate it, and no difference was found between organic and conventional foods. The proportion of organic produce found to contain pesticide residues is indeed 30 percentage points lower, but detection does not mean those levels exceed safety limits. Eating more fruits and vegetables is beneficial regardless of whether they’re organic or not. - Benefit: One systematic review brought together 17 human studies and 223 studies on food composition. Its conclusion: “There is insufficient evidence to show that organic food is significantly more nutritious than conventional food.” Again, only 3 studies examined health effects after consumption (looking at allergies and symptomatic infections), and no meaningful difference emerged. Organic produce shows a 30 percentage point reduction in pesticide residue detection rates, though detection alone does not indicate unsafe levels. The perception that organic food is a better buy stems from the common-sense chain: “no pesticides = safer = healthier.” - Evidence grade: B - Sources:Smith-Spangler C et al. (2012). Are organic foods safer or healthier than conventional alternatives?: a systematic review. Ann Intern Med. - Notes: Very few studies directly assess health outcomes after human consumption. Therefore, this finding means “there’s no evidence it’s better,” not “it’s been proven to offer no benefits.” This analysis does not address environmental impact, animal welfare, or taste preferences. Eating more fruits and vegetables remains beneficial regardless of whether they’re organic or not. ### 10. Don’t spend a lot of money on health supplements, herbal formulas, or tonics to “improve your health” - Cost: Prices range from a few hundred to tens of thousands of yuan. Once packaged as gifts, the price often multiplies several times over. - In plain terms: Multivitamins, fish oil, and vitamin D — common ingredients found in many supplements — have all been evaluated in the first six sections of this chapter, and none of them show any real benefit. The phrase “Health supplements are not medicines and cannot replace medical treatment” is a mandatory label required by regulators for all health supplements. People often buy these products for their parents or as gifts; the intention is good, but the choice of product is misguided. - Benefit: The real benefit comes from saving that money instead. The reasons are explained in the first six sections: common supplement ingredients such as multivitamins, fish oil, vitamin D, antioxidants, glucosamine, and vitamin C show no meaningful effect in randomized controlled trials; the corresponding figures appear in the “Benefit” columns of those sections. Regulatory rules only define what claims are permitted; they do not prove a product is ineffective. Chinese regulations also require that at least 20% of a health supplement’s packaging surface must display the mandatory statement: “Health supplements are not medicines and cannot replace medical treatment.” Their intended use is strictly limited to “supplementing dietary nutrients, maintaining or improving overall health, or reducing disease risk factors.” These products appear cost‑effective simply because the claim “they only help with general wellness, not curing disease” is technically true, leaving no room to disprove it. Moreover, when bought as gifts, the expense is justified by social obligation rather than scientific evidence. - Evidence grade: C - Sources:国家市场监督管理总局 (2019). 市场监管总局就《保健食品标注警示用语指南》和《保健食品原料目录与保健功能目录管理办法》有关情况举办专题新闻发布会. - Notes: The conclusion here is “no evidence supporting benefit,” not “proven ineffective,” which is why the grade is C. For products with clearly listed ingredients, check the relevant studies referenced in the earlier sections. Individuals who truly lack certain nutrients or are undergoing medical treatment should follow their doctor’s advice. What should be avoided are the products themselves, not the goodwill behind buying them. If an elderly person is already taking such supplements without substituting them for prescribed medicines and shows no adverse effects, there’s no need to intervene; instead, ensure they receive recommended vaccines and screenings. The same amount of money can be better spent on other proven measures: annual flu shots for seniors (see Section 1, Item 20); shingles vaccine after age 50 (Section 1, Item 21); pneumococcal vaccine for those over 65 (Section 1, Item 22). Purchasing a blood pressure monitor and helping them adhere to prescribed antihypertensive therapy (Section 1, Item 7) also yields clear benefits. Home modifications to bathrooms and stairs, plus exercises to improve balance and leg strength (Section 1, Item 13), are equally valuable. Age‑appropriate cancer screenings should also be arranged (Sections 1, Items 17‑19). For bedridden seniors, pressure‑ulcer prevention and long‑term care insurance are covered in Section 17, Items 7‑8. Instead of costly herbal formulas, simple gifts such as fruit, rice, or other favorite foods are far more practical. Two types of products should be avoided at all costs: investment schemes marketed as “retirement planning” and any supplements that claim to replace prescribed medicines (see Section 17, Item 5). ### 11. Don’t take probiotics long-term if you have no gut problems - Cost: Roughly 2–5 RMB per day, or 700–1800 RMB per year. - In plain terms: A review of 45 trials conducted on healthy adults shows that probiotics don’t bring about lasting changes in gut bacteria; once you stop taking them, the gut flora returns to its original state, and there’s no improvement in blood lipid levels either. Separate evidence exists for situations such as antibiotic‑induced diarrhea, but that isn’t covered here. - Benefit: This review concludes that there’s no solid proof that probiotics can produce lasting alterations in gut microbiota or improve lipid profiles in healthy adults. While gut bacteria do shift temporarily while you’re taking probiotics, these changes fade once you discontinue them. The product may seem cost‑effective simply because “gut health” is a broad term that can be applied in many ways, and the daily price per serving is quite low. - Evidence grade: B - Sources:Khalesi S et al. (2019). A review of probiotic supplementation in healthy adults: helpful or hype? Eur J Clin Nutr. - Notes: The same review also notes a few minor benefits in healthy individuals, such as firmer, better‑textured stools and an increase in Lactobacillus in women’s vaginas. Separate evidence exists for treating antibiotic‑induced diarrhea and for specific strains used for particular conditions; those are not addressed here. This recommendation applies only to healthy people who take probiotics daily as a supplement. ### 12. Don’t force yourself to take cold showers just to “boost immunity” - Cost: No cost at all. It requires enduring discomfort for 30 to 90 seconds each day; staying consistent in winter demands real willpower. People with cardiovascular conditions should be extra cautious, as cold exposure poses certain risks for them. - In plain terms: In a trial involving 3018 participants, those who took cold showers had 29% fewer sick days. However, the total number of days they took off for illness remained the same as in the control group, so it doesn’t mean they got sick less often. A 2025 systematic review combining 11 trials found that cold showers temporarily raised markers of bodily inflammation without any noticeable change in immune function. Feel free to take cold showers if you enjoy them, but don’t treat them as a worthwhile health investment. - Benefit: A randomized controlled trial conducted in the Netherlands enrolled 3018 participants. After a hot shower, they were asked to rinse under cold water for 30, 60, or 90 seconds. This group ended up taking 29% fewer sick days compared to the control group (IRR 0.71). Yet the study explicitly notes that there was no significant difference between groups regarding total sick days. No meaningful improvements were observed in quality of life, work productivity, or anxiety levels either. The 2025 review analyzed 11 randomized trials involving 3177 participants overall. It found that both immediately after and one hour post‑shower, inflammatory markers rose temporarily, while immune indicators stayed unchanged. Only at the 12‑hour mark did stress levels drop slightly. The authors themselves point out that the evidence is limited by the small number of trials and modest sample sizes. The practice seems cost‑effective only because it costs nothing, and because the intuitive belief that “enduring hardship brings benefits” makes it appealing. - Evidence grade: B - Sources:Buijze GA et al. (2016). The Effect of Cold Showering on Health and Work: A Randomized Controlled Trial. PLOS ONE. ；Cain T et al. (2025). Effects of cold-water immersion on health and wellbeing: A systematic review and meta-analysis. PLOS ONE. - Notes: Controversy: The 29% reduction in sick‑day frequency is real and unlikely to be a coincidence. Yet total illness days didn’t decrease, so it’s more plausible that participants simply kept going to work despite being unwell rather than actually getting sick less often. Using cold water for post‑exercise recovery among athletes is a separate issue and falls outside the scope of this discussion. For healthy individuals, cold showers pose no harm; this note simply warns against viewing them as a health‑promoting investment. ### 13. Don’t buy products marketed for detox, colon cleansing, enzymes, or alkaline water - Cost: Several hundred to several thousand yuan. Fasting as a way to “detox” can even lower blood sugar and cause nutritional deficiencies. - In plain terms: One review examined whether there is any evidence supporting detox diets. It concluded that while the detox industry is huge, there is very little clinical evidence to back it up, and no randomized controlled trials have ever been conducted on commercial detox diets. As for the claim that an “acidic body pH causes cancer,” a search of 8278 research papers yielded just one study that met the criteria — and even that showed no link. - Benefit: That same review reiterated that despite the rapid growth of the detox market, there is almost no clinical evidence supporting these diets, and no RCTs have been done on them. Another systematic review looked at whether diet, alkaline water, or an alkaline body pH influences cancer risk. After screening 8278 papers, only one qualified for inclusion — and it found no association. The authors concluded it is unreasonable to promote alkaline diets or alkaline water to the public as a means of preventing or treating cancer. These products seem worthwhile only because the ideas that “the body contains toxins needing removal” and “an acidic body pH causes cancer” sound plausible from a physiological standpoint. - Evidence grade: C - Sources:Klein AV, Kiat H (2015). Detox diets for toxin elimination and weight management: a critical review of the evidence. J Hum Nutr Diet. ；Fenton TR, Huang T (2016). Systematic review of the association between dietary acid load, alkaline water and cancer. BMJ Open. - Notes: This item falls under “no supporting evidence,” which is why it receives a C rating. Naturally produced metabolic waste is already cleared by the liver and kidneys; as long as these organs are healthy, there is no need for any extra “detox” measures. ### 14. Don’t force yourself to drink water just to hit “8 glasses a day” - Cost: No cost at all. It does require some time and effort to remember to drink, and you’ll likely need to get up more often at night to pee. - In plain terms: Some people have tried to trace the origin of the “8 glasses a day” rule, but no studies supporting it have ever been found. On the contrary, surveys of thousands of adults’ diets and fluid intake show there’s no need for that much water at all, since food and other drinks already provide plenty. Just drink when you’re thirsty, and use the color of your urine as a guide — that’s all you need to do. People working in hot environments, those doing intense exercise, people who’ve had kidney stones, and older adults who no longer feel thirsty as readily should make a conscious effort to drink more water. - Benefit: One literature review specifically examined the “8×8” rule — that is, 8 glasses a day, each glass holding 8 ounces of water. Its conclusion was that “no scientific research supporting the 8×8 guideline has been identified.” It also noted that “surveys of thousands of adults’ food and fluid intake strongly indicate there is no need for such a large volume of water intake,” since food and other drinks already supply plenty of moisture. This idea seems appealing because water costs nothing, the number 8 is easy to remember, and saying “drink more water” never seems like a bad piece of advice in any context. - Evidence grade: C - Sources:Valtin H (2002). "Drink at least eight glasses of water a day." Really? Is there scientific evidence for "8 x 8"? Am J Physiol Regul Integr Comp Physiol. - Notes: This recommendation refutes the idea that there’s a strict minimum number of glasses of water you must drink each day — it does not say that drinking more water is harmful. Just drink when you’re thirsty and check your urine color; that’s sufficient. People working in hot conditions, those doing heavy exercise, people with a history of kidney stones, and older adults who no longer feel thirst as keenly should make a point to drink more water, even though this guideline does not apply to them. ### 15. Don’t spend money on fortune‑telling, tarot, or astrology to make decisions - Cost: It costs nothing. The hard part is giving up a quick shortcut for making choices and having to think for yourself afterward. - In plain terms: There’s a classic classroom experiment: students receive a “personality analysis” that is identical for everyone, yet most find it very accurate. This is exactly why fortune‑telling seems reliable. Astrologers perform no better than random guesses. The price isn’t just a few dollars: in Xixian County, Henan Province, a fortune‑telling ring collected “offering fees” and “donation packages” priced up to 3,888 yuan; the ringleader was sentenced to 11 years in prison. - Benefit: In that same experiment, students rated the generic personality analysis they received after a test; 34 out of 39 gave it a score of 4 or 5 on a 0‑to‑5 scale, yielding an average of roughly 4.26. This illustrates the Barnum effect, which explains why such analyses always seem spot‑on. A double‑blind test of astrology was also published in Nature: astrologers were asked to match a client’s horoscope to one of three personality profiles; they succeeded 40 times out of 116, whereas chance alone would have yielded about 38.5 matches — far below their own expectation of 58.5. Official records show a similar pattern: prosecutors in Xixian County uncovered an online fortune‑telling scam that lured victims with free palm‑reading services, then demanded “offering fees” and “donation packages” up to 3,888 yuan. Over 50 victims lost more than 2 million yuan; the ringleader received an 11‑year sentence plus a 100,000‑yuan fine. - Evidence grade: B - Sources:Forer BR (1949). The fallacy of personal validation: A classroom demonstration of gullibility. Journal of Abnormal and Social Psychology 44(1):118-123（表 1 评分分布：2 分 1 人、3 分 4 人、4 分 18 人、5 分 16 人，N=39）. ；Carlson S (1985). A double-blind test of astrology. Nature 318:419-425（表 2：首选 116 份，挑中 40 份，随机期望 38.5，占星师预计 58.5；「The data are consistent with chance, inconsistent with astrological hypothesis」）. ，第二作者主页全文 ；最高人民检察院 (2026). 河南息县：历经三年持续追踪打掉一批网络算命诈骗团伙. - Notes: Both studies cited here are single‑experiment investigations. The average score of 4.26 for the Forer test wasn’t stated outright in the original paper; it was calculated from the distribution shown in Table 1. This note merely points out that such predictions lack accuracy; it makes no judgment about any belief system. Spending a few dollars for entertainment is fine, but using these services to decide on career moves, marriage, or investments is a costly mistake. ### 16. Don’t buy blue-light-blocking glasses to “protect your vision,” and don’t believe claims that staring at screens for months will ruin your eyes — but severe eye pain, redness, and swelling require immediate medical attention - Cost: These glasses cost nothing, and you’ll also avoid paying the extra few hundred to a few thousand yuan for blue-light-blocking lenses. - In plain terms: Blue-light-blocking lenses provide no real benefit. Skipping them saves you money, and there’s no evidence they reduce eye strain or protect the retina compared to regular lenses. While they may ease temporary eye dryness and fatigue from screen use, the only things that truly damage eyes are welding arcs, ultraviolet radiation, lasers, and acute angle-closure glaucoma. - Benefit: A 2023 Cochrane systematic review analyzed 17 randomized controlled trials, each enrolling 5 to 156 participants, with follow-up periods ranging from less than a day to five weeks. Due to limited data, significant differences in participant numbers across trials, and inconsistent follow-up times, the authors did not calculate a pooled overall effect size. All results below compare outcomes to those of people wearing regular lenses. After less than a week of use, self-reported eye fatigue showed “likely no difference” between groups, with low certainty of evidence. One trial involving 120 participants found a 9.76-unit difference between groups, with a 95% confidence interval ranging from -33.95 to 53.47 — a range spanning both positive and negative values, indicating no meaningful difference. Critical flicker fusion frequency, an objective measure of eye fatigue, also showed “likely almost no difference” between groups, with low certainty of evidence. Best corrected visual acuity after wearing the glasses showed “probably no effect” either, with a difference of 0.00 logMAR between groups (95% CI: -0.02 to 0.02). This result came from just one study with 156 participants, resulting in moderate certainty of evidence. Whether these glasses affect daytime alertness remains unclear, based on two trials with 42 participants and very low certainty of evidence. The review also found no evidence supporting any retinal protective effects of blue-light-blocking lenses. - Evidence grade: A - Sources:Singh S, Downie LE, Anderson AJ, Keller PR, White SJ, Ang M, Wolffsohn JS (2023). Blue-light filtering spectacle lenses for visual performance, sleep, and macular health in adults. Cochrane Database of Systematic Reviews, 8, CD013244. - Notes: Screen use commonly causes eye strain and dryness, which manifests as soreness, irritation, and temporary blurriness. These symptoms usually ease with rest and frequent blinking — they are temporary and do not permanently damage vision. This is a widely accepted consensus in ophthalmology, but it is not a conclusion drawn from the Cochrane review referenced here, so this point is rated as grade C evidence. The only factors that can cause irreversible eye damage in a short period are intense light sources such as welding arcs, ultraviolet radiation, and lasers. Eye injury from welding arcs, known as photic keratitis, is a legally recognized occupational disease; protection requires specialized goggles and face shields, not blue-light-blocking lenses — see Section 19, Item 10 on protection from dust, noise, and chemical hazards. For people staying up late and staring at screens, the only true emergency is severe eye pain, redness, a rainbow halo around lights, headache, nausea, and vomiting — these are signs of acute angle-closure glaucoma, which can damage the optic nerve within days and requires immediate emergency care — see Section 13, Item 6 on ophthalmic emergencies. This condition is more likely in people over 50, those with hyperopia, and those with a shallow anterior chamber, especially if they have dilated pupils in low light and maintain a forward-leaning posture for long periods. Chronic dry eye caused by prolonged screen use can also become a long-term medical issue requiring treatment, rather than a symptom that goes away after a good night’s sleep. If you experience persistent eye discomfort or a noticeable decline in vision, consult an ophthalmologist to identify the root cause — don’t assume a new pair of lenses will resolve the problem. For advice on preventing myopia in children and teens, see Section 30, Items 4, 12, and 9: get at least two hours of outdoor time daily, undergo mydriatic refraction tests, and avoid products marketed as “myopia cures.” ### 17. Don’t treat blood donation as a health habit: claims that it “detoxifies, lowers cholesterol, and prevents heart attacks” lack randomized trial support, while frequent donation truly causes iron deficiency - Cost: There is no monetary cost. A single donation — including registration, drawing blood, and post-donation observation — takes about an hour. Over the following weeks, the body works to replenish the lost iron. - In plain terms: The idea that donating blood helps “detoxify,” lowers cholesterol, or prevents heart attacks is not reliable. Those conclusions stem from observational data, and people who regularly donate are generally healthier to begin with. When this baseline difference is accounted for, the original claim that “each additional yearly donation lowers mortality by 18.6%” drops to just 7.5%. One actual randomized trial found no difference in death rates between donors and non-donors. On the other hand, donating too often does make people feel weak and cold — precisely because of iron loss. - Benefit: The Kuopio study in Finland followed 2862 men aged 42–60 for nearly nine years. In the 24 months prior to tracking, 153 men donated blood; only one (0.7%) suffered an acute heart attack. Among the remaining 2529 non-donors, 316 (12.5%) experienced the same outcome (P<0.0001). After adjusting for age and other coronary risk factors, donors showed an 88% lower risk of heart attack; the relative risk was 0.12 (95% CI 0.02–0.86, P=0.035). However, this result came from an observational study without randomization. The Nordic SCANDAT database included 1182495 donors observed over 9526627 person-years; 15401 deaths occurred. After controlling for age and gender, each extra yearly donation lowered mortality by 18.6% (95% CI 16.8%–20.4%). Once the fact that only healthy individuals are allowed to donate was factored in, the benefit fell to 7.5% (95% CI 5.7%–9.4%). Researchers concluded this does not constitute solid proof of health benefits. The FeAST randomized trial enrolled 1277 patients with symptomatic peripheral artery disease; one group received regular blood removal every six months to reduce iron levels, while the other served as a control. Overall mortality rates were 125 out of 636 (20%) versus 148 out of 641 (23%). HR 0.85 (95% CI 0.67–1.08, P=0.17). Combined outcomes of death, heart attack, and stroke also showed no significant difference: 180 out of 205 (28% vs 32%) with HR 0.88 (95% CI 0.72–1.07, P=0.20). The INTERVAL trial involved 45263 whole-blood donors divided into three groups based on donation intervals: 12 weeks, 10 weeks, or 8 weeks for men; 16 weeks, 14 weeks, or 12 weeks for women. Shorter intervals indeed yielded more blood within two years (the 8-week group produced 1.69 extra units compared to the 12-week group, 95% CI 1.59–1.80). Yet no differences emerged in quality of life, physical activity, or cognitive function. However, more donors reported fatigue, shortness of breath, dizziness, lightheadedness, and restless legs — especially at night. Average hemoglobin and ferritin levels also dropped, and more donations were postponed due to low hemoglobin (all P<0.0001). Iron deficiency impairs heat production: ten women with iron-deficiency anemia, eight with depleted iron stores but no anemia, and twelve controls were immersed in 28°C water for 100 minutes. The anemia group’s rectal temperature averaged 36.0±0.2°C versus 36.2±0.1°C in controls (P=0.001); oxygen consumption was 5.28±0.26 versus 5.99±0.29 mL·min⁻¹·kg⁻¹ (P=0.04). Thyroid hormones thyroxine and triiodothyronine were also lower (P<0.002). This pattern occurs because donors are repeatedly screened for good health; the hypothesis that “removing iron protects the heart” has not been confirmed in randomized trials. - Evidence grade: A - Sources:Salonen JT, Tuomainen TP, Salonen R, Lakka TA, Nyyssönen K (1998). Donation of blood is associated with reduced risk of myocardial infarction. The Kuopio Ischaemic Heart Disease Risk Factor Study. American Journal of Epidemiology, 148(5), 445-451. ；Ullum H, Rostgaard K, Kamper-Jørgensen M, et al. (2015). Blood donation and blood donor mortality after adjustment for a healthy donor effect. Transfusion, 55(10), 2479-2485. ；Zacharski LR, Chow BK, Howes PS, et al. (2007). Reduction of iron stores and cardiovascular outcomes in patients with peripheral arterial disease: a randomized controlled trial. JAMA, 297(6), 603-610. ；Di Angelantonio E, Thompson SG, Kaptoge S, et al. (2017). Efficiency and safety of varying the frequency of whole blood donation (INTERVAL): a randomised trial of 45 000 donors. Lancet, 390(10110), 2360-2371. ；Beard JL, Borel MJ, Derr J (1990). Impaired thermoregulation and thyroid function in iron-deficiency anemia. American Journal of Clinical Nutrition, 52(5), 813-819. ；全国人大常委会 (1997). 中华人民共和国献血法（第二、九、十四条）. ；国家卫生健康委等 (2024-01-08). 关于进一步做好无偿献血者激励奖励工作的通知. - Notes: This entry does not oppose blood donation itself, but rather the notion that it serves as a personal health practice. Donated blood is used for others, and according to the beneficiary classification in this book, it falls under category 4, which refers to strangers. What actually benefits the donor is the policy-related perks. Article 14 of the Blood Donation Law stipulates that unpaid blood donors are exempt from fees related to blood collection, storage, separation, and testing when using blood services themselves; their spouses and direct relatives may also be exempt or receive fee reductions as specified by provincial governments. In January 2024, the National Health Commission announced that 55 provinces and regions have implemented policies allowing unpaid blood donors and their relatives to have such hospital fees waived directly at discharge. Those who receive the National Blood Donation Award are also eligible for local “three free” policies, which cover free public transport, free entry to government-run parks, and waived outpatient consultation fees at public hospitals. Donors should adhere to the legally mandated intervals: Article 9 of the Blood Donation Law states that each donation should be 200 milliliters at minimum and 400 milliliters at maximum, with at least six months between donations. The recommended age range for donation is 18–55 years. Do not shorten the interval merely to meet honor criteria or group targets. Women, those with lower body weight, and individuals with heavy menstrual flow already have limited iron reserves; regular donors may opt for a self-funded ferritin test. If persistent fatigue, cold intolerance, or restless legs at night occur after donation, these are not signs of “vital energy depletion” but likely due to iron deficiency; a blood test and ferritin check are advised, followed by iron supplementation and extended donation intervals as directed by a doctor. The evidence for cold intolerance specifically comes from a study involving just 2024 participants, and this figure is included here solely to illustrate the phenomenon, not to indicate how many people experience it. ### 18. Don’t rely on generic health check packages to prevent disease; instead, get the evidence‑based screenings appropriate for your age and gender - Cost: There’s no cost at all; you even save hundreds to thousands of yuan each year by avoiding these packages. The trade‑off is simply remembering which tests you need and how often to get them. - In plain terms: People who regularly undergo generic health checks have the same mortality rates as those who don’t, including deaths from cardiovascular disease and cancer. It’s enough to get the evidence‑based screenings that match your age and gender. Individuals over 35 can have their blood pressure measured for free once a year, and those 65 or older receive a free annual health check. - Benefit: The 2019 update of a Cochrane systematic review included 17 randomized controlled trials. When looking at overall mortality, data from 11 of those trials involving 233,298 participants and 21,535 deaths showed no difference: the RR was 1.00 (95% CI 0.97–1.03). For deaths from cardiovascular disease, nine trials with 170,227 participants and 6,237 deaths yielded an RR of 1.05 (95% CI 0.94–1.16); for cancer deaths, eight trials with 139,290 participants and 3,663 deaths gave an RR of 1.01 (95% CI 0.92–1.12). In each case there was no meaningful difference. The authors concluded that generic health checks are unlikely to provide any real benefit. As part of the national basic public health service, residents aged 35 and older can have their blood pressure measured for free each year, while those 65 and older receive a free annual physical exam. This exam includes a physical examination, complete blood count, urinalysis, fasting blood glucose, electrocardiogram, and tests for liver function (AST, ALT, total bilirubin), kidney function (serum creatinine, blood urea), and lipid profile (total cholesterol, triglycerides, LDL‑C, HDL‑C). An abdominal ultrasound of the liver, gallbladder, pancreas, and spleen is also offered nationwide. - Evidence grade: A - Sources:Krogsbøll LT, Jørgensen KJ, Gøtzsche PC (2019). General health checks in adults for reducing morbidity and mortality from disease. Cochrane Database of Systematic Reviews, 1, CD009009. ；国家卫生计生委 (2017). 国家基本公共卫生服务规范（第三版）（老年人健康管理服务、高血压患者健康管理服务）. - Notes: What we’re discouraging is using annual check‑up packages as a preventive measure; it doesn’t mean you should skip all tests. The free annual blood pressure measurement for those over 35 and the free annual physical for seniors are already part of the national public health program, so there’s no need to pay for them. Get tested for any condition you have a reason to screen for. Information on blood pressure, blood glucose, and hepatitis B can be found in sections 7, 8, and 14 of Chapter 1; breast, cervical, and colorectal cancer screening details appear in sections 17, 18, and 19. Helicobacter pylori testing and low‑dose CT screening are covered in sections 23 and 24. Bone density testing for women over 65 is described in section 39. If you’ve engaged in high‑risk behaviors, follow the guidance in section 31. The recommended ages and intervals for each test are listed there. Feel free to attend any employer‑sponsored or other paid health screenings; the warning applies only to buying full packages or adding extra tests at your own expense. People with chronic diseases, symptoms, or those prescribed tests by a doctor are excluded from this advice — those are medical treatments, not screening. The most commonly offered tests with little or no evidence base are tumor markers and whole‑body imaging; see section 7 for PET‑CT scans and tumor marker panels. For cases of elevated uric acid or silent gallstones, refer to sections 19 and 20 respectively. Finally, note that most of the Cochrane trials were conducted in high‑income countries where healthcare access is easy; this conclusion may not be directly applicable to regions with limited medical resources. ### 19. Don’t start taking uric‑acid‑lowering drugs just because a checkup shows high uric acid but you’ve never had symptoms - Cost: There’s no cost at all; you also avoid long‑term medication expenses, regular follow‑ups, and the risks linked to unnecessary drug use. - In plain terms: People whose uric acid levels are high but who’ve never had gout attacks or tophus deposits mainly gain peace of mind from taking uric‑acid‑lowering drugs. According to calculations by the American College of Rheumatology, you’d need to treat 24 people for three full years just to prevent a single gout episode. These drugs also won’t protect your kidneys; in randomized trials the rate of kidney‑function decline was identical in patients taking them and those on a placebo. What truly helps is keeping weight, alcohol, and sugary drinks in check — and only treating gout after an actual attack occurs. - Benefit: The 2020 gout guidelines from the American College of Rheumatology address asymptomatic hyperuricemia, defined as blood uric‑acid levels above 6.8 mg/dL in people who’ve never had gout or tophus. Under certain conditions the guidelines advise against initiating any uric‑acid‑lowering therapy — drugs such as allopurinol, febuxostat, or probenecid. Evidence supporting this recommendation is rated “high.” A footnote clarifies that, based on attributable risk, 24 patients must be treated for three years to prevent one gout episode. The CKD‑FIX trial enrolled 363 participants with stage 3 or 4 chronic kidney disease; they had no gout history but faced a higher risk of worsening kidney function. One group received 100–300 mg of allopurinol daily while the other got a placebo; after 104 weeks the annual change in eGFR — a key kidney‑function marker measured in mL/min/1.73 m² — was –3.33 (95 % CI –4.11 to –2.55) in the drug group versus –3.23 (–3.98 to –2.47) in the placebo group. The difference between groups was –0.10 (–1.18 to 0.97), with a P‑value of 0.85, meaning kidney‑function decline proceeded at the same pace. Serious adverse events occurred in 46 % of patients on allopurinol versus 44 % on placebo. The PERL trial involved 530 type 1 diabetics with early‑to‑moderate diabetic kidney disease; after three years of allopurinol therapy the drug was withdrawn for two months to gauge its effect. Allopurinol lowered blood uric‑acid from 6.1 mg/dL to 3.9 mg/dL, yet after discontinuation the eGFR difference between groups narrowed to just 0.001 mL/min/1.73 m² (95 % CI –1.9 to 1.9, P = 0.99). Moreover, urinary albumin excretion rose 40 % (range 0–80 %) in the allopurinol group. The apparent “benefit” stems largely from the intuitive notion that any elevated marker warrants medication. - Evidence grade: A - Sources:FitzGerald JD, Dalbeth N, Mikuls T, et al. (2020). 2020 American College of Rheumatology Guideline for the Management of Gout. Arthritis Care & Research, 72(6), 744-760（表 1 及其脚注）. ；Badve SV, Pascoe EM, Tiku A, et al. (2020). Effects of Allopurinol on the Progression of Chronic Kidney Disease. New England Journal of Medicine, 382(26), 2504-2513. ；Doria A, Galecki AT, Spino C, et al. (2020). Serum Urate Lowering with Allopurinol and Kidney Function in Type 1 Diabetes. New England Journal of Medicine, 382(26), 2493-2503. - Notes: This recommendation specifically discourages lifelong uric‑acid‑lowering therapy in people who’ve never experienced gout; it does not imply that high uric‑acid levels are harmless. The same guidelines outline exceptions where treatment may be warranted: first‑time gout attacks accompanied by stage 3 or higher chronic kidney disease, blood uric‑acid levels exceeding 9 mg/dL (≈535 µmol/L), or a history of uric‑acid kidney stones. Those who’ve already had gout attacks, have tophus deposits, or show bone erosion on imaging should indeed start medication — see Section 16, Item 9 for details. Roughly 7.4 % of Han Chinese carry the HLA‑B*5801 genotype, compared to just 0.7 % of Caucasians; carriers face a markedly higher risk of life‑threatening hypersensitivity reactions, with Asian patients three times more prone to severe skin syndromes than white patients. Given this risk, it’s prudent to avoid allopurinol unless absolutely necessary; testing for the HLA‑B*5801 variant before prescribing is advisable, as noted in Section 16, Item 9. The kidney studies involved patients with chronic kidney disease or type 1 diabetes, so their findings shouldn’t be extrapolated to suggest that high uric‑acid levels are completely benign for all kidneys. They merely refute the claim that uric‑acid‑lowering drugs protect kidney function. ### 20. Don’t have a gallbladder removed prophylactically just because an ultrasound found gallstones but you’ve never felt any pain - Cost: There’s no cost at all — you even avoid the expense of general anesthesia and a hospital stay. The trade-off is simply remembering a few warning signs that mean you must seek medical care right away. - In plain terms: For people with gallstones but no pain, roughly 80% remained symptom-free over the next nine years. Without any intervention, only about 0.1% to 0.3% develop acute cholecystitis or pancreatitis each year. Gallbladder removal isn’t risk-free either: roughly 1.5% of patients suffer bile duct injury. That’s why European and UK medical guidelines recommend against surgery when there are no symptoms. - Benefit: In Italy, the MICOL study followed 11,229 people aged 29 to 69 using ultrasound screening. Of those, 856 had gallstones; 580 had none at all. After an average of 8.7 years of follow-up, 453 of those 580 (78.1%) stayed symptom-free, 61 (10.5%) experienced mild symptoms, and 66 (11.4%) had severe symptoms. During that time, 189 gallbladder removals were performed, and 41.3% of those surgeries were on patients without any symptoms. The study authors concluded that watchful waiting remains the best approach for most patients. Another US study of 691 patients with gallstones showed that among 135 symptom-free patients followed for an average of 58 months, only 10% developed symptoms and 7% needed surgery. Of all 50 deaths recorded, just two were linked to the bile ducts, and both occurred in patients with symptoms. The authors stressed that people with silent gallstones shouldn’t undergo surgery before symptoms appear. UK NICE guidelines explicitly state that people with no symptoms and normal bile ducts don’t need treatment. European liver disease guidelines note that each year, 0.7% to 2.5% of symptom-free patients develop symptoms, while 0.1% to 0.3% suffer acute cholecystitis, pancreatitis, jaundice, or cholangitis. After the first episode of pain, that risk rises to 1% to 3% annually. Swedish national data show that 1.5% of 51,041 gallbladder removals cause bile duct injury, with 0.3% resulting in partial or total duct rupture; mortality within a year is 3.9% for those with injury versus 1.1% otherwise. Even after surgery, 10% to 40% of patients still experience discomfort. Overall, guidelines agree that surgery doesn’t extend life expectancy for symptom-free patients, and the procedure’s risks outweigh those of leaving the organ intact. Waiting until symptoms appear also saves money. One 1983 estimate found that a 30-year-old man who chooses prophylactic removal lives 4 days less on average, while a 50-year-old loses 18 days. To date, no randomized trials have compared prophylactic removal to watchful waiting, yet the idea that “it’s better to remove it now before pain starts” remains common. - Evidence grade: A - Sources:Festi D, Reggiani ML, Attili AF, et al. (2010). Natural history of gallstone disease: Expectant management or active treatment? Results from a population-based cohort study. Journal of Gastroenterology and Hepatology, 25(4), 719-724. ；McSherry CK, Ferstenberg H, Calhoun WF, Lahman E, Virshup M (1985). The natural history of diagnosed gallstone disease in symptomatic and asymptomatic patients. Annals of Surgery, 202(1), 59-63. ；National Institute for Health and Care Excellence (2014). Gallstone disease: diagnosis and management. NICE guideline CG188，第 1.2.1、1.3.1 条. ；European Association for the Study of the Liver (2016). EASL Clinical Practice Guidelines on the prevention, diagnosis and treatment of gallstones. Journal of Hepatology, 65(1), 146-181. ；Törnqvist B, Strömberg C, Persson G, Nilsson M (2012). Effect of intended intraoperative cholangiography and early detection of bile duct injury on survival after cholecystectomy: population based cohort study. BMJ, 345, e6457. ；Ransohoff DF, Gracie WA, Wolfenson LB, Neuhauser D (1983). Prophylactic cholecystectomy or expectant management for silent gallstones. A decision analysis to assess survival. Annals of Internal Medicine, 99(2), 199-204. ；Gurusamy KS, Samraj K (2007). Cholecystectomy versus no cholecystectomy in patients with silent gallstones. Cochrane Database of Systematic Reviews, CD006230. ；反方：Venneman NG, Buskens E, Besselink MG, et al. (2005). Small gallstones are associated with increased risk of acute pancreatitis: potential benefits of prophylactic cholecystectomy? American Journal of Gastroenterology, 100(11), 2540-2550. ；中华医学会外科学分会胆道外科学组, 中国医师协会外科医师分会胆道外科医师委员会 (2022). 胆囊良性疾病外科治疗的专家共识（2021版）. 中华外科杂志, 60(1), 4-9. （全文需订阅，未取得）；同上 (2022). 《胆囊良性疾病外科治疗的专家共识（2021版）》解读. 中华外科杂志, 60(4), 337-342. - Notes: This topic is still debated. China’s 2021 expert consensus on biliary surgery includes some asymptomatic gallstone cases as surgical candidates, and related commentary highlights this controversy as a key point of discussion. The exact criteria for those exceptions haven’t been verified yet. Another counterpoint concerns small stones: those under 5 mm are more closely linked to pancreatitis, and Dutch research suggests prophylactic removal might either extend or shorten life depending on how common and severe pancreatitis is in a given population. European guidelines do list two exceptions: porcelain gallbladder and gallstones over 1 cm alongside large polyps — both warrant removal. Removal may also be considered during other major abdominal surgeries. Crucially, this advice applies only to stones inside the gallbladder with no prior symptoms; stones in the common bile duct are a completely different matter. UK and European guidelines both stress that stones in the bile duct must be removed along with the gallbladder, regardless of symptoms. Seek emergency care immediately if you experience persistent upper abdominal pain, fever, chills, yellowing of the eyes or skin, or dark urine. When a doctor recommends surgery after reviewing imaging, ask which specific criteria prompted that decision — whether it’s bile duct involvement, polyps, or abnormal gallbladder walls — so you can weigh those factors against this general guideline, which is meant to discourage surgery without any valid medical reason. Both cited studies tracked patients over 4 to 9 years, focusing on what happens when no intervention is taken; they don’t compare treatment effectiveness. Longer follow-ups would likely show a higher rate of symptom development. 〔61.6〕 〔50.2〕 〔46.3〕 〔188〕 〔2016〕 ### 21. Don’t cut calcium out to prevent kidney stones - Cost: No cost at all. In fact, it’s easier — no need to constantly watch what foods contain calcium. - In plain terms: People who’ve had calcium oxalate stones are often advised to limit calcium intake, but randomized trials show the opposite. A study with 120 men who repeatedly developed stones divided them into two groups: one ate a normal amount of calcium while cutting back on animal protein and salt; the other followed a traditional low‑calcium diet. After five years, recurrence rates were 12 out of 60 versus 23 out of 60 — meaning the normal‑calcium group had half the risk. UK guidelines also advise against restricting calcium. - Benefit: This five‑year randomized trial enrolled 120 men with recurrent calcium oxalate stones and high urinary calcium levels. One group consumed 30 mmol of calcium daily, reduced animal protein to 52 g per day, and limited salt to 50 mmol of sodium chloride; the control group ate only 10 mmol of calcium daily. Over five years, recurrence occurred in 12/60 versus 23/60 participants. The unadjusted relative risk was 0.49 (95% CI 0.24–0.98; P = 0.04), indicating half the risk with normal calcium intake. Both groups saw a similar drop in urinary calcium — about 170 mg per day — but oxalate excretion fell by 7.2 mg/day in the normal‑calcium group versus a rise of 5.4 mg/day in the low‑calcium group. NICE guideline NG118 states adults should aim for 700–1200 mg of calcium daily; children and teens need 350–1000 mg per day. The perception that cutting calcium is beneficial stems from the intuitive idea that “stones are made of calcium, so less calcium must help.” - Evidence grade: A - Sources:Borghi L, Schianchi T, Meschi T, et al. (2002). Comparison of two diets for the prevention of recurrent stones in idiopathic hypercalciuria. New England Journal of Medicine, 346(2), 77-84. ；National Institute for Health and Care Excellence (2019). Renal and ureteric stones: assessment and management. NICE guideline NG118，第 1.8.1 条. - Notes: Caveats: This trial involved only men with recurrent calcium oxalate stones and high urinary calcium; results may not apply to all stone types. Moreover, the intervention group simultaneously reduced protein and salt intake, so some benefits could stem from those changes rather than calcium alone. This advice specifically discourages actively eliminating calcium‑rich foods — it does not advocate extra calcium supplementation. For any need to add calcium pills, consult your physician. Regarding hydration, see Section 16, Item 8: drinking 2.5–3 L of water daily after a stone episode. ### 22. Don’t buy crystals, bracelets, or Pixiu figurines for “good luck,” “wealth attraction,” or “health benefits” - Cost: There is no monetary cost involved. The only requirement is to avoid listing “good luck,” “health benefits,” or similar claims as reasons for purchase. The real challenge is resisting the urge to buy them when everyone else is wearing them and talking about their magical powers. - In plain terms: There is absolutely no verifiable evidence supporting claims that wearing such items can change one’s fate, attract wealth, or improve health. These assertions work on the same principle as fortune-telling: they are phrased so vaguely that people naturally interpret them as applying to themselves. Any explicit health or fortune-related claims made by sellers would constitute illegal false advertising; in 2026, several livestream shops were penalized for exactly this reason. Buying them purely as decorative accessories is perfectly fine, but allocating extra funds specifically for “luck enhancement” is what this guidance aims to prevent. - Benefit: Classic classroom experiments demonstrate that when participants receive the same generic “personality analysis,” they almost universally deem it accurate. This phenomenon is known as the Barnum effect, and it explains why many people feel that wearing these items somehow improves their lives. The underlying conclusion is simple: personal acceptance of a vague statement does not validate its factual accuracy. A notable official case involves a jewelry shop in Sihui, Guangdong, which was penalized by China’s State Administration for Market Regulation on June 4, 2026. During livestream sales, the shop falsely advertised that its products could prevent rheumatism, boost immunity, improve sleep, and even clear blood vessels. By fabricating elaborate narratives, the business misled consumers, violating Article 9, Paragraph 1 of China’s Anti-Unfair Competition Law. Only 34 people actually need to be aware of this principle for it to have a meaningful impact on consumer behavior. - Evidence grade: B - Sources:Forer BR (1949). The fallacy of personal validation: A classroom demonstration of gullibility. Journal of Abnormal and Social Psychology. ；国家市场监督管理总局 (2026). 市场监管总局公布一批传统工艺市场「打假清源」典型案例. - Notes: This entry serves one main purpose: to emphasize that there is no scientific basis for any claimed benefits, nor any measurable predictive power. It does not pass judgment on personal beliefs or cultural traditions, nor does it discourage buying such items as gifts, mementos, or family heirlooms. Two points must be clearly distinguished: legally enforceable claims about product performance can be reported to authorities, while vague notions like “good luck” lack any research support and cannot be proven false; thus, personal budget control is the only practical safeguard. Before purchasing, treat the item strictly as a decorative piece and ask yourself: “If it offered no magical benefits at all, would I still pay this price?” For guidance on verifying materials and certifications, or why treating them as investments is unwise, refer to Sections 5.33 and 5.34. Information on spending money on fortune-tellers is provided in Section 5.15. 〔33〕 ### 23. Don’t expect shopping to lift your mood or boost your sense of self-worth - Cost: No cost at all. The hard part is resisting the urge to buy things when you’re feeling down. - In plain terms: On average, people who place a higher value on money and material possessions report lower levels of happiness. This conclusion comes from a meta-analysis of 259 separate studies, though the link between the two is fairly weak and it’s unclear which factor drives the other. Other research comparing spending on experiences versus physical goods found that money spent on experiences tends to bring more satisfaction. So when you’re in a bad mood, reallocating your budget toward a day out or a meal with friends is far more likely to help than adding more items to your shopping cart. - Benefit: This meta-analysis combined data from 259 independent studies, covering a total of 753 effect sizes. The results showed that individuals who prioritize material possessions tend to report lower happiness levels. On the most commonly used multi-dimensional well‑being scale, the correlation coefficient was r = –0.19 (adjusted ρ = –0.24). When only the single dimension of “valuing money” was measured, the correlation weakened to r = –0.08 to –0.11. The strength of this link varied depending on the specific outcome measured: it was strongest with risky health‑related and consumption behaviors and negative self‑evaluations (r = –0.28 to –0.44) and weakest with overall life satisfaction and negative emotions (r = –0.13 to –0.15). Mediation analyses suggested that this negative relationship may arise because psychological needs remain unmet. Another set of studies asked different groups of participants whether spending on experiences or on goods made them happier; respondents consistently chose experiences. Laboratory experiments confirmed this: recalling a purchase made for an experience produced a better mood than recalling a purchase of a physical item. Both studies used overseas samples, so these findings don’t apply to the Chinese population. - Evidence grade: B - Sources:Dittmar H, Bond R, Hurst M, Kasser T (2014). The relationship between materialism and personal well-being: A meta-analysis. Journal of Personality and Social Psychology, 107(5), 879-924. ；Van Boven L, Gilovich T (2003). To do or to have? That is the question. Journal of Personality and Social Psychology, 85(6), 1193-1202. - Notes: Caveats: Most of the included studies surveyed the same group of people at a single point in time, so they can’t determine which factor comes first. The authors themselves note that further experiments and long‑term follow‑ups are needed to clarify the direction of this relationship. Therefore, this recommendation should not be interpreted as “shopping makes people unhappy”; rather, it means “relying on shopping to improve your mood is unlikely to succeed.” The overall correlation is modest: r = –0.19 accounts for only a few percentage points of variation, and individual differences are considerable. Since both studies used foreign samples, there are no comparable Chinese data to cite. This advice does not discourage spending on items you genuinely enjoy; it simply warns against using shopping as a mood‑regulation tool, as that can lead to repeated impulse buys when you’re feeling down. Specific ways to save money are described in Section 5. Evidence‑based strategies for coping with low mood can be found in the latter part of Section 22 and in Section 29. Information on budgeting to “outperform” others is covered in Item 24 of this section. ### 24. Don’t spend extra money to “move up a rung” among your peers by buying a new house, car, or social circle - Cost: No cost at all. All you need to do is ask one extra question before increasing your budget: is this extra expense buying a real product, or simply securing a higher status among your peers? The difficulty lies in resisting the urge to upgrade when everyone else does. - In plain terms: When comparing people with similar incomes, those whose neighbors earn more report lower happiness levels. This effect appears only among neighbors with comparable education and frequent social interaction. Thus, spending extra money to move into a neighborhood where everyone is wealthier actually pushes you down the social ladder. Yet when incomes rise across the board, people still feel better off, so absolute levels of happiness remain relevant. - Benefit: The National Survey of Family and Households (NSFH) in the U.S. surveyed the same individuals twice. Researchers matched these results with local average incomes calculated from a 5% sample of the 1990 census. After adjusting for personal characteristics and income, they found that higher neighbor incomes correlate strongly with lower self-reported happiness. This effect holds across multiple analytical methods and remains highly statistically significant. In fact, the drop in happiness caused by a rise in neighbor incomes matches the drop produced by a comparable fall in one’s own income. Even after controlling for individual-level factors or limiting comparisons to the same state and survey round, the pattern persists. This rules out explanations such as happier people naturally moving to poorer areas, unmeasured state-level variables, or differences between renters and homeowners. The effect is strongest among individuals with close neighbor ties, while those who socialize mainly outside their community show no such trend. Happiness declines only when comparing with neighbors of similar education; income differences among less educated neighbors have little impact. The mechanism appears to work mainly through satisfaction with one’s material circumstances rather than other life domains. Finally, when both personal and neighbor incomes rise proportionally, overall happiness still increases. - Evidence grade: B - Sources:Luttmer EFP (2005). Neighbors as Negatives: Relative Earnings and Well-Being. The Quarterly Journal of Economics, 120(3), 963–1002. ；Luttmer EFP (2004). Neighbors as Negatives: Relative Earnings and Well-Being. NBER Working Paper No. 10667（本条引用的表述与数量级按这一版逐字核对）. - Notes: Several reasons justify a B rating: the data come from repeated surveys of the same participants, this is the sole study of its kind, and the sample is foreign; the measured outcome is self-reported happiness rather than monetary figures. Researchers applied multiple statistical controls, such as within-person comparisons and comparisons limited to the same state and survey round, but the study is still not a randomized trial. No comparable data exist for Chinese populations. The benefit magnitude is classified as “moderate” following the criteria established in section 23 (don’t expect material purchases to boost happiness). The potential savings can indeed reach tens of thousands of yuan; however, because no quantitative link exists between those savings and actual happiness gains, they are not classified as “large.” This advice does not discourage spending on larger homes, quieter neighborhoods, or shorter commutes when those features themselves are valued. What it discourages is spending solely to avoid feeling inferior to colleagues or peers. For guidance on how to prioritize housing choices, see section 4, item 18 (give priority to commute time when selecting a residence). For information on using purchases to improve mood, refer to section 23 (don’t expect material purchases to boost happiness). Regarding the tendency to constantly compare oneself with others online, see section 3, item 20 (don’t make “how others are doing” a daily obsession). ### 25. Don’t believe that “willpower is like a muscle that runs out after use” - Cost: No cost at all. All that needs changing is the way we talk about it. - In plain terms: The popular idea is that after doing something that requires self‑control, it becomes easier to give in to temptation later on, so we should “save” our willpower. Yet 23 laboratories and 2,141 participants repeated this experiment using the same protocol, and the results were essentially null. Stop using “I’ve run out of willpower today” as an excuse, and don’t spend money on courses that promise to help you conserve it. - Benefit: In a multi‑lab preregistered replication study, 23 labs with 2,141 participants followed Sripada et al.’s standardised procedure: first they performed a task demanding self‑control, then a second similar task. The pooled results showed a very small self‑exhaustion effect; its 95 % confidence interval included 0 (d = 0.04, 95 % CI −0.07 to 0.15). Another replication, also preregistered, involved 36 labs and 3,531 participants and yielded d = 0.06 — again a negligible effect. These findings call into question the model that self‑control is a limited resource. - Evidence grade: A - Sources:Hagger MS, Chatzisarantis NLD, Alberts H, et al. (2016). A Multilab Preregistered Replication of the Ego-Depletion Effect. Perspectives on Psychological Science, 11(4), 546–573. ；Vohs et al. (2021). A Multisite Preregistered Paradigmatic Test of the Ego-Depletion Effect. Psychological Science. - Notes: What’s being refuted is the notion that self‑control is a consumable resource, not that people can become fatigued. Lack of sleep or prolonged effort does reduce performance, but that falls under the guidelines on sleep and working hours in Section 3. The only evidence‑based actions are environmental tweaks and simple wording changes, as described in Section 4, items 10 (“move unwanted items out of reach”) and 1 (“write down exactly when, where and what you’ll do”). Fixing routine choices such as clothing and diet is still worthwhile because it costs almost nothing. It saves minutes and mental effort, not “willpower”; don’t expect it to improve your judgment later in the day. While other items in this section deal with monetary costs, this one concerns time and mental energy, which aren’t interchangeable. ### 26. Don’t expect skipping breakfast or the 16:8 intermittent fasting method to help you control your weight; instead, pick a meal timing you can stick to long-term - Cost: There’s no monetary cost. What you save is the mental energy you’d otherwise spend worrying about meal timing. - In plain terms: Popular belief holds that skipping breakfast leads to overeating at lunch and dinner, ultimately increasing total daily calorie intake. Research does not support this: people who skipped breakfast consumed over 200 fewer calories per day on average, and ended up slightly lighter. Compared to simply eating less overall, 16:8 intermittent fasting produces no meaningful difference in weight after a full year. That said, people who regularly skip breakfast do have a roughly 17% higher risk of cardiovascular disease; no significant difference in overall mortality has been observed, however. - Benefit: Let’s first address the claim that skipping breakfast causes people to eat more later in the day. One meta-analysis combined data from 13 randomized trials. Participants assigned to eat breakfast consumed 259.79 kcal more per day on average than those who skipped it (95% CI 78.87–440.71). Their body weight was also 0.44 kg higher (95% CI 0.07–0.82). However, people who skipped breakfast did not make up for those missing calories at subsequent meals. All these trials had very short follow-up periods: an average of 7 weeks for weight tracking, and just 2 weeks for measuring calorie intake. Next, we look at 16:8 intermittent fasting, which restricts eating to a specific window each day. One trial involved 116 overweight adults over 12 weeks. The group limited their eating to 12 p.m. to 8 p.m. showed no significant weight difference compared to those eating three regular meals daily: a difference of −0.26 kg (95% CI −1.30 to 0.78). Another trial conducted in Guangzhou followed 139 obese patients for 12 months. Those who combined time-restricted eating with calorie restriction lost 1.8 kg more on average than those only controlling calorie intake (95% CI −4.0 to 0.4), a difference that also failed to reach statistical significance. Finally, we examine whether long-term breakfast skipping is harmful. A pooled analysis of 2.38 million people found that skipping breakfast raised cardiovascular disease risk by 17% (OR 1.17, 95% CI 1.09–1.26), and cardiovascular-related mortality by 49% (OR 1.49, 95% CI 1.20–1.84). These findings come from observational studies that did not assign participants to breakfast or non-breakfast groups. One original study with 17–23 years of follow-up reported a 1.19-fold higher all-cause mortality risk for breakfast skippers (95% CI 0.99–1.42), a figure that crosses 1 but is not statistically significant. - Evidence grade: A - Sources:Sievert K, Hussain SM, Page MJ, 等 (2019). Effect of breakfast on weight and energy intake: systematic review and meta-analysis of randomised controlled trials. BMJ. ；Lowe DA, Wu N, Rohdin-Bibby L, 等 (2020). Effects of Time-Restricted Eating on Weight Loss and Other Metabolic Parameters in Women and Men With Overweight and Obesity. JAMA Internal Medicine. ；Liu D, Huang Y, Huang C, 等 (2022). Calorie Restriction with or without Time-Restricted Eating in Weight Loss. New England Journal of Medicine. ；Zhang H, Zhang S, Liu Y, 等 (2025). The association between skipping breakfast and cardiovascular disease: a meta analysis. Frontiers in Cardiovascular Medicine. ；Rong S, Snetselaar LG, Xu G, 等 (2019). Association of Skipping Breakfast With Cardiovascular and All-Cause Mortality. Journal of the American College of Cardiology. ；Fernandes-Alves D, Teixeira GP, Guimarães KC, Crispim CA (2026). Systematic Review and Meta-analysis of Randomized Clinical Trials Comparing Time-Restricted Eating With and Without Caloric Restriction for Weight Loss. Nutrition Reviews. ；Sun T, Zhang L, Lu Y, 等 (2024). Non-linear relationship between the first meal time of the day and gallstone incidence in American adults. Frontiers in Nutrition. ；Liu T, Wang Y, Wang X, 等 (2023). Habitually Skipping Breakfast Is Associated with the Risk of Gastrointestinal Cancers: Evidence from the Kailuan Cohort Study. Journal of General Internal Medicine. - Notes: This topic remains controversial. The 17% rise in cardiovascular disease risk stems from observational studies without controlled group assignments. Breakfast skippers also tend to smoke more, drink more alcohol, lead more sedentary lifestyles, and have lower incomes; these factors are not fully accounted for in the data, so it is unclear how much of this risk is directly attributable to skipping breakfast. The all-cause mortality finding also crosses 1 but lacks statistical significance. 16:8 intermittent fasting is similarly debated: a pooled analysis of 30 trials involving 1,341 participants showed that when both groups ate the same amount of food, the time-restricted eating group lost 1.46 kg more on average (95% CI −2.65 to −0.26), but at the cost of losing 0.41 kg more lean body mass. Most of these trials were very short in duration; the longest and most rigorous 12-month trial found no meaningful weight difference between the two groups. Prolonged fasting may also affect gallbladder health. One cross-sectional survey of 6,547 people found that for every hour later a person ate their first meal, their risk of gallstones rose by 5% (OR 1.05, 95% CI 1.02–1.08); those whose first meal was between 9 a.m. and 2 p.m. had a 49% higher risk compared to earlier eaters (OR 1.49, 95% CI 1.24–1.77). The underlying mechanism is that bile remains in the gallbladder longer, increasing the likelihood of stone formation. However, this is a cross-sectional study, so it is possible that existing gallbladder issues prompted people to change their eating habits. The Kaiping Cohort Study in China followed 369 cases of digestive tract cancer over 5.6 years: breakfast skippers had a 2.32-fold higher risk of colorectal cancer (95% CI 1.34–4.01) and a 5.43-fold higher risk of gallbladder and extrahepatic bile duct cancer (95% CI 1.34–21.93). The very wide confidence interval for the latter figure indicates very few events occurred, so this should be viewed as a preliminary clue rather than conclusive evidence. Overall, when it comes to weight control, meal timing has minimal impact; there is no need to spend mental energy on this factor. As for whether long-term breakfast skipping is beneficial, all available evidence is correlational, not causal, but the trend leans toward negative outcomes. To be on the safe side, it is better to eat regular meals; don’t expect skipping breakfast to help you lose weight. The primary causes of gastritis and gastric ulcers are Helicobacter pylori infection and long-term use of painkillers; details are covered in Section 1, Item 23. For people who have gallstones detected via checkups but never experience pain, guidance is provided in Section 1, Item 20. To effectively control weight, proven strategies are eating enough fruits and vegetables (Section 2, Item 27), cutting back on ultra-processed foods (Section 2, Item 28), and keeping BMI within 20–25 (Section 2, Item 32). These recommendations do not apply to people with diabetes, those taking blood sugar-lowering medication, or pregnant individuals; skipping meals could lead to hypoglycemia in these groups, so they must follow their doctor’s instructions. Extreme fasting and induced vomiting are separate issues altogether; see Section 28, Item 1 for details. ### 27. Don’t believe claims that masturbation harms health or that abstaining improves wellbeing; what really matters is whether it interferes with sleep, work, or relationships - Cost: Zero. You save money you’d otherwise spend on dubious “kidney‑tonic” remedies, “abstinence” courses, and the chronic anxiety that comes from self‑blame. - In plain terms: No credible research shows masturbation harms health. One large U.S. study found men who ejaculated more often had roughly 20% fewer cases of prostate cancer. A British study, however, noted a higher risk among men who reported frequent ejaculation in their twenties and thirties, so neither figure should be taken as a health‑boosting prescription. Many people who feel “addicted” to pornography actually struggle because the behavior clashes with their personal moral beliefs. - Benefit: A U.S. study followed 31,925 men through 2010, asking each to report how often they ejaculated each month. Compared with men ejaculating 4–7 times monthly, those ejaculating more than 21 times had a hazard ratio of 0.81 (95% CI 0.72–0.92) for prostate cancer — a roughly 19% reduction — when the count was measured at ages 20–29. At ages 40–49 the ratio was 0.78 (0.69–0.89), a roughly 22% drop, mainly affecting low‑risk prostate cancers. A British case‑control study of 431 prostate‑cancer patients and 409 controls found a higher risk for men reporting frequent masturbation in their twenties and thirties, but a lower risk for those who reported it frequently after age 50. Regarding pornography, a meta‑analysis concluded that many people labeling themselves “addicted” are simply experiencing a conflict between their actions and personal values, rather than being driven solely by excessive exposure. - Evidence grade: B - Sources:Rider JR, Wilson KM, Sinnott JA, et al. (2016). Ejaculation Frequency and Risk of Prostate Cancer: Updated Results with an Additional Decade of Follow-up. European Urology, 70(6), 974–982. ；Dimitropoulou P, Lophatananon A, Easton D, et al. (2009). Sexual activity and prostate cancer risk in men diagnosed at a younger age. BJU International, 103(2), 178–185. ；Grubbs JB, Perry SL, Wilt JA, Reid RC. (2019). Pornography Problems Due to Moral Incongruence: An Integrative Model with a Systematic Review and Meta-Analysis. Archives of Sexual Behavior, 48(2), 397–415. - Notes: This topic remains controversial. Both prostate‑cancer studies merely observed correlations without controlled groups, and the frequency figures were self‑reported, so the evidence only supports the conclusion that there is no evidence of harm; it does not justify encouraging more frequent ejaculation. The British authors themselves note that the later‑age protective effect could reflect illness preceding reduced activity. The pornography meta‑analysis did not provide effect sizes, so only a directional trend is reported. The modest benefit rating reflects that the reduction applies mainly to low‑risk prostate cancers, not to mortality. Red flags that warrant a visit to a psychiatrist or psychologist include chronic sleep loss, missed work, damaged relationships, and an inability to cut back despite wanting to. For sleep issues, see Section 3, Item 9 (avoid staying up late for games, short videos, or porn). If you’re concerned about erectile problems linked to porn use, follow Section 1, Item 28: get a cardiovascular check‑up first. Legal consequences of sharing or selling pornographic material are outlined in Section 9, Item 4. Ultimately, the only person who benefits is you. ### 28. Don’t spend money on “sexual orientation conversion” or “gay conversion therapy,” and don’t send your family members to such programs - Cost: No cost at all. What you save is the money you would otherwise spend on conversion clinics, counseling centers, and the revenue generated by these “conversion” services. The real challenge is getting family members to accept that this isn’t necessary. - In plain terms: After reviewing relevant research, an expert panel from the American Psychological Association concluded that these conversion efforts cannot change a person’s sexual orientation and may actually cause harm. In one U.S. survey, nearly 90% of people who had undergone conversion therapy reported having suicidal thoughts. In China, a psychiatric hospital forcibly admitted a man under the label of “sexual preference disorder”; a court later ruled this a violation of his rights and ordered the hospital to pay him 5,000 yuan in compensation. - Benefit: The 2009 APA task force report states that attempts to change sexual orientation “are unlikely to succeed and carry a certain risk of harm.” It also advises both parents and children to avoid any mandatory or inpatient conversion programs for minors. A nationwide U.S. survey of 1,518 LGBTQ+ adults found that about 7% had undergone conversion therapy; 80% of them were referred by religious figures. After adjusting for age and childhood trauma, people who had undergone conversion therapy had a 92% higher odds of having had suicidal thoughts at some point in their lives (OR 1.92, 95% CI 1.01–3.64). Their odds of having planned a suicide attempt were 75% higher (OR 1.75, 1.01–3.06), and their odds of attempting suicide without serious injury were 88% higher (OR 1.88, 1.01–3.50). Another study of 245 young adults aged 21–25 found that 22% of those who had never undergone conversion therapy attempted suicide; this figure rose to 48.1% among those whose parents tried to change their orientation, and to 62.8% among those whose parents sent them to therapists or religious figures for conversion. WHO’s ICD-10 classification explicitly states that “sexual orientation itself is not considered a disorder.” In 2017, a court in Zhumadian, Henan Province, ruled that a psychiatric hospital had violated a man’s rights by forcibly admitting him under the “sexual preference disorder” label; the court noted that his condition was mild and he showed no suicidal or violent tendencies, so he did not meet criteria for mandatory treatment. The court ordered the hospital to issue a public apology and pay 5,000 yuan in compensation for emotional distress (U.S. and China). - Evidence grade: B - Sources:American Psychological Association Task Force on Appropriate Therapeutic Responses to Sexual Orientation (2009). Report of the Task Force on Appropriate Therapeutic Responses to Sexual Orientation. ；Blosnich JR, Henderson ER, Coulter RWS, Goldbach JT, Meyer IH. (2020). Sexual Orientation Change Efforts, Adverse Childhood Experiences, and Suicide Ideation and Attempt Among Sexual Minority Adults, United States, 2016–2018. American Journal of Public Health, 110(7), 1024–1030. ；Ryan C, Toomey RB, Diaz RM, Russell ST. (2020). Parent-Initiated Sexual Orientation Change Efforts With LGBT Adolescents: Implications for Young Adult Mental Health and Adjustment. Journal of Homosexuality, 67(2), 159–173. ；World Health Organization. ICD-10 Version:2019, F66 Psychological and behavioural disorders associated with sexual development and orientation. ；全国人大常委会 (2018 年修正). 精神卫生法（第二十三、三十、七十八条）. ；广西壮族自治区人民检察院网站转载新京报 (2017). 驻马店「同性恋强制治疗案」终审. ；反方：Sullins DP. (2022). Sexual Orientation Change Efforts Do Not Increase Suicide: Correcting a False Research Narrative. Archives of Sexual Behavior, 51, 3377–3393. ；Blosnich JR, Coulter RWS, Henderson ER, et al. (2023). Correcting a False Research Narrative: A Commentary on Sullins (2022). Archives of Sexual Behavior, 52(3), 885–888. - Notes: This topic remains controversial. In 2022, Sullins reanalyzed the same dataset while excluding participants who already reported suicidal thoughts prior to conversion therapy; this analysis showed no significant link between conversion therapy and suicidal thoughts (OR 0.44, 0.20–0.94). Sullins’ organization opposes LGBTQ+ rights, and the original study authors have responded to these findings. While the extent of harm caused by conversion therapy is still debated, there is no credible evidence contradicting the fact that such therapy cannot change sexual orientation. This study was assigned a Grade B rating because all data on potential harm were collected via retrospective self-report surveys. Legally, involuntary hospitalization is permitted only for individuals with severe mental disorders who pose a risk of harming themselves or others; voluntary participation is required for all other cases. Mental health professionals are prohibited from providing conversion therapy. Intentionally admitting someone without a mental disorder to a psychiatric facility can result in legal liability. Individuals struggling emotionally due to this issue may seek help from psychiatrists or clinical psychologists to alleviate their distress. Guidance on how families should respond after a child comes out is provided in Section 30, Item 15 (“When a child says they’re attracted to the same sex”). The primary beneficiaries of avoiding conversion therapy are both you and your family members.