Could your daily coffee be linked to less body fat and more muscle?

But new research from Finland suggests regular coffee drinkers may differ from non-drinkers in some unexpected ways - including having less body fat, more muscle, and several healthier metabolic markers. The study , published in the European Journal of Nutrition, analysed data from 2,264 participants in the Northern Finland Birth Cohort 1966, all of whom were age 46 when assessed. The researchers compared the participants’ usual coffee intake with measures including body composition, blood metabolites and sex hormone levels.

The most eye-catching finding was that people who drank more coffee tended to have lower levels of both overall and abdominal fat, while also having greater skeletal muscle mass. Interestingly, their body mass index (BMI) was not necessarily lower.

That distinction matters because BMI only compares weight with height; it does not reveal whether that weight comes from fat, muscle or a combination of the two. In other words, two people can have similar BMIs while having quite different body compositions.

Higher coffee intake was also associated with lower levels of branched-chain amino acids in the blood. These amino acids are a normal part of the diet, but persistently high levels have previously been linked with insulin resistance and a greater risk of developing type-2 diabetes.

That does not mean coffee prevents diabetes, but it offers researchers another possible clue as to why earlier studies have repeatedly linked coffee drinking with better metabolic health. Lead researcher Luca Verroest said the study uncovered a distinctive metabolic and hormonal pattern that remained even after factors such as BMI and lifestyle were taken into account.

Among women, higher coffee intake was linked with some differences in hormone levels, although researchers say more work is needed to understand what this means. (Envato Elements pic) Some of the clearest hormone-related findings appeared among men. Those who drank more coffee tended to have a more favourable glucose and insulin profile, along with higher levels of total testosterone and a protein called sex hormone-binding globulin (SHBG).

At the same time, free testosterone levels were slightly lower. Among women, the hormonal links were less extensive.

Higher coffee intake was mainly associated with higher SHBG and lower measures of free androgens. Researchers are still trying to understand what these patterns mean and whether hormones might partly explain coffee’s apparent relationship with metabolism.

Don’t order the extra-large latte just yet

There is an important catch: this was an observational study, meaning the researchers found relationships between coffee drinking and certain health markers, but they did not prove that coffee itself caused those differences.

People who drink more coffee may also differ in other ways - diet, sleep, activity levels or other habits - that could influence the results. The study also did not establish an ideal amount of coffee to drink. Nor does it mean increasing coffee intake will automatically reduce body fat or build muscle.

For now, the findings are best viewed as another piece of a much larger puzzle surrounding one of the world’s most popular drinks - and Finland is an especially fitting place to investigate the subject, given its famously strong coffee culture.