Does caffeine increase fat metabolism?
Yes. The effects aren't massive, but you don't need much to kick-start the effect
Quick Summary
This meta-analysis of randomised controlled trials shows that caffeine boosts fat metabolism a bit to a lot, regardless of how much you take.
What was studied?
The researchers investigated the impact of caffeine intake on fat metabolism, including fat oxidation.
Study Participants
A total of 984 young adults (average age 26; comprising 84% men and 16% women) were included in the study.
Methodology
Examining 94 randomised controlled trials, the researchers studied varying doses of caffeine (1-15 mg per kg body weight). Most studies (63%) assessed the effects on fasted participants (≥3 hours since their last meal).
Fat metabolism effects were measured using expired gas analysis and blood biomarkers such as free fatty acids and glycerol levels. Subgroup analyses evaluated whether sex, fitness level or caffeine dosage influenced outcomes.
Results
Caffeine gave a small to moderate jump in fat burning. The gains were stronger for the relaxers than those doing exercise, but not when you looked at them together. Sex, fitness, and dosage had no effect on the results.
Additional Information
Despite dose-independent results for fat oxidation being unexpected – given ergogenic (performance-enhancing) effects can be increased by dose – it is possible that performance-enhancing attributes are separate from positive impacts on fat metabolism.
So, you only need one cup if it’s fat-burning you’re trying to influence. Even if only by a little bit.
Here’s the paper if you want to take a look.