A large Finnish study published in 2026 in the European Journal of Nutrition found that habitual coffee drinkers had less total and visceral fat, more skeletal muscle mass, and more favorable metabolic markers than people who drank less coffee — even when both groups had a similar BMI.
The study also reported distinct hormonal patterns: men who drank more coffee had higher total and bioavailable testosterone (but modestly lower free testosterone), while both men and women showed lower levels of branched-chain amino acids that have been linked to insulin resistance and type 2 diabetes risk.
Here's what the research actually found — and what it doesn't prove.
The Study at a Glance
Researchers at the University of Oulu analyzed data from 2,264 adults (age 46) enrolled in the Northern Finland Birth Cohort 1966. They examined how participants' usual coffee intake related to circulating metabolites, cardiometabolic risk markers, and sex hormone levels.
Finland is the world's highest coffee-consuming country, averaging approximately 11.8 kg (26 lbs) per person annually. That makes this cohort especially relevant for studying long-term associations between coffee and metabolic health.
The lead author is Luca Verroest, a Doctoral Researcher at the University of Oulu. The full paper, "Associations of habitual coffee intake with testosterone and cardiometabolic markers," is published in the European Journal of Nutrition.
Less Fat, More Muscle — Despite Similar BMI
The headline finding: people who consumed more coffee tended to have lower levels of both total body fat and visceral fat (the fat stored around internal organs), along with greater skeletal muscle mass.
What makes this particularly interesting is that participants with higher and lower coffee intake had a similar BMI. In other words, coffee drinkers in this cohort weren't simply thinner — they had a different body composition. Less fat, more muscle, same scale weight. The study cannot say why.
For anyone using cold brew as a pre-workout, it sits alongside existing research on caffeine and exercise performance — though this study did not test that.
Lower Branched-Chain Amino Acids
Higher coffee consumption was associated with lower circulating concentrations of branched-chain amino acids (BCAAs) in both men and women. When chronically elevated, BCAAs have been linked to insulin resistance and a greater risk of developing type 2 diabetes.
This is consistent with previous research reporting that coffee consumption is associated with reduced cardiometabolic risk. The BCAA finding adds another possible biological mechanism — a hypothesis, not a demonstrated pathway.
The Testosterone Connection
Some of the clearest differences appeared among men. Greater coffee consumption was associated with:
- A more favorable glucose-insulin profile
- Higher total and bioavailable testosterone
- Higher sex hormone-binding globulin (SHBG)
- Modestly lower free testosterone and free androgen index
That last point matters: the picture is not simply "coffee raises testosterone." It's a mixed hormonal signature.
The hormonal picture in women was less extensive. Higher coffee intake was mainly associated with increased SHBG and lower measures of free androgens.
As Verroest explained: "What stood out in our findings was a distinct hormonal signature that didn't disappear even after we took into account BMI and lifestyle factors, with several of these associations differing between men and women."
The researchers suggest that hormonal pathways could help explain some of the previously observed relationship between coffee consumption and metabolic health.
What This Means for Coffee Drinkers
If you already drink coffee daily — especially unsweetened cold brew — this study adds to a growing body of evidence that habitual coffee consumption is associated with favorable metabolic markers. Association is not causation, and nothing here is a reason to start or stop drinking coffee for health purposes.
The key associations worth noting:
- Body composition: Less visceral fat, more skeletal muscle
- Metabolic markers: Lower BCAAs
- Hormonal profile: Higher total and bioavailable testosterone and SHBG in men; modestly lower free testosterone
- Cardiometabolic health: More favorable glucose-insulin profile in men
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Shop Bare Brew →Important Caveats: What This Study Does NOT Prove
This was an observational study, not a randomized controlled trial. It found associations between coffee intake and body composition, metabolic markers, and hormones — but it cannot prove that coffee directly caused any of these differences.
People who drink more coffee may differ from those who drink less in ways the study couldn't fully account for, even after adjusting for BMI and lifestyle factors. The researchers themselves note that additional research — including animal models and eventually human intervention studies — will be necessary before these findings can shape dietary recommendations.
It's also worth noting that all participants were 46-year-old Finnish adults from a single birth cohort. Results may not apply to other age groups or populations. And the study examined coffee generally — not cold brew, and not any specific product.
The Bigger Picture
This study adds to a growing stack of evidence linking habitual coffee consumption to favorable metabolic markers. From the 2026 AHA statement on coffee and heart health to research on coffee and metabolic pathways, much of the recent observational literature has been broadly favorable toward moderate coffee intake for most healthy adults. Individual circumstances vary — talk to your doctor.
What makes these findings particularly interesting is the body composition angle. BMI alone doesn't distinguish between fat and muscle. Two people at the same BMI can have very different profiles depending on their ratio of visceral fat to lean mass. This study suggests coffee drinkers in this cohort sat on the favorable side of that ratio.
If you're thinking about your caffeine intake, the type of coffee matters too. A clean caffeine source — without added sugar, artificial sweeteners, or synthetic additives — means you're drinking coffee's own compounds without an added sugar load on top.
Study Details
Full citation: Verroest, L., Jokelainen, J., Choudhary, S., Walkowiak, J., Karhu, T., Palaniswamy, S., Auvinen, J., Jarvelin, M-R., Herzig, K-H., & Raza, G.S. (2026). Associations of habitual coffee intake with testosterone and cardiometabolic markers: the Northern Finland Birth Cohort 1966 study. European Journal of Nutrition. DOI: 10.1007/s00394-026-04038-z
Coverage: Science Daily — Coffee drinkers have less fat, more muscle, and surprising hormone differences
Frequently Asked Questions
Does coffee increase testosterone?
This observational study found that men who drank more coffee had higher total and bioavailable testosterone. However, the study cannot prove that coffee directly increases testosterone — only that an association exists. Free testosterone and the free androgen index were actually modestly lower in higher coffee consumers. More research, including controlled trials, is needed.
Can coffee help you lose fat and build muscle?
The Finnish study found that coffee drinkers had less total and visceral body fat and more skeletal muscle mass than people who drank less coffee, even at similar BMIs. However, this was observational — it does not show that coffee caused the difference, and drinking coffee is not a substitute for exercise and proper nutrition.
How much coffee did people in the study drink?
The study examined habitual coffee intake among 2,264 Finnish adults aged 46. Finland is the world's highest coffee-consuming country, averaging about 11.8 kg (26 lbs) of coffee per person per year. The study looked at varying levels of consumption and their associated metabolic and hormonal markers.
Is cold brew coffee better for body composition than regular coffee?
This study did not compare brewing methods, so there's no evidence either way. The associations were with habitual coffee intake generally. Separately, cold brew has a lower total titratable acidity than hot brew (though pH is comparable), and unsweetened cold brew like Bare Brew's two-ingredient formula has no added sugar.
What are branched-chain amino acids, and why do they matter?
Branched-chain amino acids (BCAAs — leucine, isoleucine, and valine) are essential amino acids. While they're important for muscle protein synthesis, chronically elevated circulating BCAA levels have been associated with insulin resistance and increased type 2 diabetes risk. This study found that higher coffee intake was linked to lower circulating BCAA levels in both men and women.
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Honduran Arabica coffee and filtered water. 320mg of natural caffeine and 20 calories per can. No sugar, no additives.
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