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In A Nutshell
- Black coffee came out ahead. In a Tufts University study of more than 46,000 U.S. adults, one to two cups a day of black coffee, or coffee with little added sugar and saturated fat, was linked to a 14% lower risk of death from any cause, the university reported.
- Heavy add-ins wiped out the link. Coffee with high amounts of added sugar and saturated fat showed no lower risk of death.
- A teaspoon may be fine. A larger 2022 study in the U.K. found that people who added about a teaspoon of sugar per cup still had a lower risk of dying than non-coffee drinkers.
- Association, not proof. These are observational studies, so they cannot show that coffee itself extends life.
For millions of Americans, the day does not start until the coffee is poured. Then comes the second ritual: the cream, the sugar, the flavored syrup, the whipped topping.
A growing body of research suggests that the first habit may be good for you. A large U.S. study now suggests the second may cancel it out. Here is what the research on coffee and longevity shows, and why what goes into the cup may matter as much as the coffee itself.
What Did The Tufts Study Find?
Black or lightly sweetened coffee was linked to a lower risk of death. Heavily loaded coffee was not.
Researchers at Tufts University’s Friedman School of Nutrition Science and Policy analyzed data from 46,222 adults who took part in the National Health and Nutrition Examination Survey between 1999 and 2018, then linked it to national death records. They sorted coffee by type and by how much sugar and saturated fat people added.
Drinking one to two cups of caffeinated coffee a day was linked to a lower risk of death from all causes and from cardiovascular disease. For black coffee and coffee with low levels of added sugar and saturated fat, the risk was 14% lower than for people who drank no coffee. At two to three cups a day, the link rose to 17%, according to Tufts. The same link was not seen for coffee with high amounts of added sugar and saturated fat. The findings were published in The Journal of Nutrition in 2025.
How Much Sugar Is Too Much?
In the Tufts analysis, “low” meant very little.
The study defined low added sugar as less than 2.5 grams per 8-ounce cup, roughly half a teaspoon. Overall, the benefit faded once added sugar, saturated fat or both went above about 5 percent of the daily value. “Our results align with the Dietary Guidelines for Americans which recommend limiting added sugar and saturated fat,” said first author Bingjie Zhou.
A different study offers some reassurance for people who cannot drink it black. In 2022, researchers analyzing 171,616 participants in the U.K. Biobank found that people who drank 1.5 to 3.5 cups a day, either unsweetened or with about a teaspoon of sugar, were 29% to 31% less likely to die over seven years than non-coffee drinkers, the study in Annals of Internal Medicine reported. Results for artificially sweetened coffee were less consistent.
Why Would Coffee Matter At All?
Researchers suspect its natural compounds, though they cannot prove it.
Coffee contains caffeine along with many other bioactive compounds, including antioxidants. The Tufts team suggested those compounds may explain the lower risk, and that large amounts of sugar and saturated fat may work against them.
Both studies are observational. Coffee drinkers may differ from non-drinkers in ways the researchers could not fully measure, so the results show a link, not proof that coffee lengthens life. Caffeine also affects people differently, as StudyFinds explored in why coffee makes some people sleepy.
What’s The Takeaway For Your Morning Cup?
If you enjoy coffee, the evidence suggests keeping it simple.
Most people do not need to give up coffee. The studies above looked at roughly one to three cups a day. The bigger question is what you add. A splash of milk or a little sugar appears unlikely to cancel the benefit. A large flavored drink loaded with syrup and cream is a different product, and in the Tufts data, it showed no lower risk at all.
The coffee may be doing its part. The trick, according to this research, is not to undo it on the way to the lid.
