Drink three to four cups of coffee a day, keep total caffeine at or under 400 mg, and add no sugar and no milk foam

People who drink three to four cups of coffee a day have about a 17% lower chance of dying over the same period than people who do not drink it. In another study, people who drank their coffee in the morning had about a 12% lower chance, and people who drank it all day showed no difference. The caffeine in one cup varies a lot, so keep the daily total at or under 400 mg.

Cost

Brewing it yourself costs one or two yuan a day. A cup takes a few minutes and does not take much time. If you buy large cups, watch how many milligrams of caffeine you have had in a day.

Benefit

One review pooled analyses of 201 observational studies. The original studies under those pooled analyses only recorded what people did; they did not assign people to groups. On overall mortality, the review cited one of those pooled analyses of dose and effect. People who drank 3–4 cups of coffee a day, compared with people who drank none, had a 17% lower risk of death (relative risk 0.83, 95% CI 0.79–0.88, the confidence interval). At 7 cups a day, the reduction shrank to 10% (relative risk 0.90, 95% CI 0.85–0.96), and the risk was not seen to turn back up. A study from the U.S. National Health and Nutrition Examination Survey (NHANES) followed 40 725 adults. Half of them were followed for a full 9.8 years. It also only recorded; it did not assign groups. The study split coffee drinkers into two kinds. Morning-type drinkers took their coffee between 4:00 and 11:59 and hardly drank any in the afternoon or evening. They were 36%. Compared with people who drank no coffee, their risk of death from all causes was 12% lower (hazard ratio 0.88, 95% CI 0.81–0.96). After also taking out the effect of short sleep and trouble sleeping, it was 16% lower (hazard ratio 0.84, 95% CI 0.74–0.95). The risk of death from cardiovascular disease was 19% lower (hazard ratio 0.81, 95% CI 0.70–0.94). After taking out the effect of sleep, it was 31% lower (hazard ratio 0.69, 95% CI 0.55–0.87). All-day drinkers drank in the morning, the afternoon, and the evening. They were 16%. Their risk of death from all causes showed no difference (hazard ratio 0.99, 95% CI 0.90–1.10). Neither kind showed a difference in the risk of death from cancer. The daily caffeine ceiling has an official basis. Both the European Food Safety Authority (EFSA) and Health Canada set the ceiling for healthy adults at 400 mg a day. That is all sources added together. Tea, cola, and energy drinks count too. EFSA also says to spread it through the day, with no single occasion over 200 mg. One cup varies a lot. In EFSA's table, a 200 mL cup of filter coffee is about 90 mg. In Health Canada's table, an 8-ounce (237 mL) cup of brewed coffee averages 135 mg. In the U.S. Food and Drug Administration (FDA) table, 12 ounces (about 355 mL) of brewed coffee contains 113–247 mg. So the FDA turns 400 mg into about 2 to 3 cups of 12-ounce coffee, and the review turns it into about 4 cups.

Notes

The dispute is this: the review authors state that most of the evidence comes from studies that only followed and recorded, and that reliable randomized trials are needed before anyone can say it is causal. The point that morning is better rests on one U.S. study, so it is not in the title. The authors state that the result cannot be read as causal, and that it may only be that people who drink coffee in the morning live healthier lives overall. In another U.S. study limited to people with diabetes, people who drank coffee from dawn through the morning had a 25% higher risk of death, and people who drank from morning through noon had a 20% lower risk. The results run the other way. None of these studies compared whether 12:00 or 14:00 is the better line. Item 4 of section 3 (no caffeine after 2 p.m.) is about sleep. Count back from your own bedtime. It does not conflict with this item. 400 mg is a safety ceiling, not a dose that has been shown to help. Decaffeinated coffee has a similar benefit, only a bit smaller, so there is no need to drink more just to make up the amount. Pregnant women stay at or under 200 mg a day (EFSA) or 300 mg (Health Canada). This item does not apply to women whose fracture risk is high. It also does not apply to people with anxiety or insomnia. That is this book's judgment. The review has no conclusion for those two groups. People with atrial fibrillation do not all have to give up coffee. In one trial, after electrical cardioversion for persistent atrial fibrillation, people who drank about 1 cup of coffee a day had fewer recurrences than people who quit (47% versus 64%). The 2023 U.S. atrial fibrillation guideline also does not recommend giving up coffee to prevent episodes, but people whose symptoms are set off by drinking should cut down. There is no evidence for other arrhythmias. Follow the doctor. On mortality, adding sugar was not seen to cancel the benefit. Syrups and milk-foam drinks have not been studied, and the sugar in them is large, so the advice is still not to add them.

Sources · 10

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2. Yang R, Lei Q, Liu Z, et al. (2024). Relationship between timing of coffee and tea consumption with mortality (total, cardiovascular disease and diabetes) in people with diabetes: the U.S. National Health and Nutrition Examination Survey, 2003–2014. BMC Medicine, 22, 526. doi.org/10.1186/s12916-024-03736-x
3. EFSA Panel on Dietetic Products, Nutrition and Allergies (2015). Scientific Opinion on the safety of caffeine. EFSA Journal, 13(5), 4102. doi.org/10.2903/j.efsa.2015.4102
4. EFSA 咖啡因专题页（每份含量表）efsa.europa.eu/en/topics/topic/caffeine
5. FDA. Spilling the Beans: How Much Caffeine Is Too Much? fda.gov/consumers/consumer-updates/spilling-b…
6. Health Canada. Caffeine in foods. canada.ca/en/health-canada/services/food-nutr…
7. 加糖：Liu D, Li ZH, Shen D, et al. (2022). Association of Sugar-Sweetened, Artificially Sweetened, and Unsweetened Coffee Consumption With All-Cause and Cause-Specific Mortality. Annals of Internal Medicine, 175(7), 909-917. doi.org/10.7326/M21-2977
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