A team of scientists, including researchers from the Karolinska Institute in Sweden, reports that low-calorie caffeinated drinks such as tea without milk and black coffee may be linked to reductions in body fat. The findings appear in BMJ Medicine, underscoring a potential connection between caffeine intake and body composition for adults in North America and beyond.
Experts note that the level of caffeine circulating in the bloodstream can influence fat stores. In their analysis, the researchers used genetic data from nearly 10,000 individuals to explore how genes that govern caffeine metabolism affect body fat. They looked specifically at variants in the CYP1A2 and AHR genes, which alter how quickly caffeine is broken down and cleared from the body.
Participants carrying certain mutations in CYP1A2 and AHR metabolize caffeine more slowly, keeping it in the blood longer. Higher plasma caffeine concentrations have been associated with a lower body mass index and reduced total body fat mass, although there is an observed link to a higher risk of developing type 2 diabetes in some contexts. The authors emphasize that short-term studies have shown caffeine intake can drive weight and fat loss, potentially through boosted energy expenditure and altered fat oxidation. They propose that caffeine may raise thermogenesis and promote fat burning, thereby accelerating metabolism. Still, the long-term consequences of regular high-caffeine consumption remain unclear and likely depend on overall lifestyle, diet, and individual genetics.
Historical scholars noted that coffee can sharpen cognitive performance, a notion echoed in later research that connects caffeine with alertness and mental focus. Yet the latest findings remind readers that metabolism, genetics, and daily habits together shape how caffeine affects body composition over time.