Coffee Drinkers May Have More Muscle, Less Body Fat and Unexpected Hormone Differences, According to a New Study

If your morning routine begins with coffee, a new study from Finland offers a reason to look beyond the simple question of whether the drink is “good” or “bad” for you.

Researchers found that adults who drank more coffee tended to have less total body fat, less visceral fat around the midsection, and more skeletal muscle mass than those who drank less.

Yet the most interesting detail was not a difference on the scale. Participants had broadly similar body mass indexes, suggesting that body composition, not just weight, differentiated the groups.

So, what was the study about?

A Snapshot of 2,264 Finnish Adults

The participants were all 46 years old, all drawn from the same Finnish birth cohort, and all examined at the same stage of life.

Published in the European Journal of Nutrition on August 19, 2026, the study examined data from 2,264 participants in the Northern Finland Birth Cohort 1966. Researchers looked at habitual coffee intake alongside body composition, metabolic markers, cardiometabolic indicators, and sex hormone levels.

Finland, which has the highest per-capita coffee consumption in the world, provided a useful setting for examining differences in coffee habits within a similar population. Because everyone in the study was the same age, researchers were able to remove one common variable that can complicate health research.

The study was cross-sectional, meaning it captured information at one point in time rather than tracking participants over years. As a result, the findings show patterns but cannot determine what caused them.

The BMI Finding That Changes the Story

Weight alone didn’t explain what researchers were seeing, and the gap between what a scale shows and what a body is actually made of is where the study gets interesting.

Coffee drinkers and non-coffee drinkers in the study had broadly similar body mass indexes. However, when researchers looked deeper, they found differences in body composition. Higher coffee intake was associated with lower total body fat, lower visceral fat, and greater skeletal muscle mass.

Lead researcher Luca Verroest, a doctoral researcher at the University of Oulu, said the findings showed that “people with the same BMI can have quite different amounts of fat versus muscle.” In this group, people who drank more coffee appeared to have a leaner fat-to-muscle profile that a standard weight measurement would not reveal.

That matters because BMI does not separate fat mass from muscle mass. Two people can have the same number on a scale while having very different body compositions. The researchers’ findings highlight why weight alone may not tell the complete health story.

Related: Why Your Daily Coffee Could Be the Secret to Better Wellness

A Metabolic Signal Shared Across Sexes

Beyond body composition, researchers found a consistent pattern in specific metabolic markers, one that connects to several serious conditions in prior research.

Higher coffee intake was linked with lower circulating levels of branched-chain amino acids, or BCAAs, among both men and women.

The study authors described the relationship between coffee consumption and lower BCAA levels as “particularly noteworthy.” However, the researchers also emphasized that the finding does not show whether coffee directly changes BCAA clearance or whether it reflects other differences among people who drink more coffee.

Among men, higher coffee intake was also associated with a more favorable glucose-insulin profile. Because coffee itself is not a meaningful dietary source of BCAAs, coffee cannot simply be explained by replacing another food or nutrient.

The Hormone Picture Is More Complicated Than Headlines Suggest

Among men, higher habitual coffee intake was associated with higher total testosterone, higher bioavailable testosterone, and higher sex hormone-binding globulin, or SHBG.

But the picture became more complicated when researchers looked at other measures. Free testosterone and the free androgen index were modestly lower in the higher-coffee groups.

For women, the hormone pattern was more limited. Higher coffee intake was mainly associated with higher SHBG and lower free-androgen measures.

“Coffee appears to leave a measurable fingerprint on the body’s metabolism and hormones, and that fingerprint looks different in men than in women,” Verroest said. Still, the study cannot determine whether coffee itself produced these hormonal differences or whether other lifestyle factors among coffee drinkers played a role.

Coffee Is Not Just Caffeine

Attributing these associations to caffeine alone misses much of what makes the science unresolved.

Coffee contains more than 1,000 bioactive compounds, including chlorogenic acids and trigonelline in addition to caffeine. Registered dietitian Monique Richard said the response “may depend on the whole coffee matrix, not simply caffeine alone. There probably isn’t one coffee compound responsible.”

The study did not identify which part of coffee, if any, might explain the patterns researchers observed.

For now, the research adds another layer to the story of a drink many people consume every day. Coffee may be more biologically complex than its reputation as simply a source of caffeine suggests.

What This Research Doesn’t Change

The study doesn’t establish an ideal number of cups or suggest that coffee can substitute for lifestyle factors with the strongest long-term evidence.

The researchers did not identify a recommended daily coffee intake for improving body composition or hormonal health. Although participants drinking five or more cups daily had the lowest average body-fat percentage and greatest skeletal muscle mass in the study, the design cannot show that those differences came from drinking more coffee.

Coffee habits also had limits to how precisely they could be measured. Intake was self-reported, and researchers did not account for serving size, roast, bean type, or additions such as sugar and cream.

The type of coffee matters, too. Then, physical activity, adequate protein, sleep, and overall diet quality remain central factors in body composition and metabolic health. Coffee may eventually prove to be one piece of that larger picture.

However, researchers still need to separate the effects of coffee itself from the habits often associated with coffee drinkers.

If body composition rather than weight turned out to be the more meaningful health measure for you, would it change how you track your health day to day?

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