Research

Energy balance

Caffeine ingestion increases 24-hour energy expenditure and lipid oxidation in lean women, but this thermogenic response is significantly blunted in duration and magnitude in obese women.

If you are obese, caffeine will still increase your daily energy expenditure and fat burning, but the effect is about half as strong as it is in lean individuals, and it does not extend into the night. Do not rely on caffeine alone for weight loss in obesity; its utility as a thermogenic agent is significantly diminished compared to lean populations.

GoodQualifiesHIGH confidence
The magnitude of thermogenesis was smaller in obese (4.9 +/- 2.0%) than in lean subjects (7.6 +/- 1.3%). The thermogenic response to caffeine was prolonged during the night in lean women only.
David Bracco et al. · American Journal of Physiology-Endocrinology and Metabolism · 1995

Why this rating

Randomized, double-blind, crossover design using whole-body respiration chambers (gold standard for EE measurement) with a sufficient sample size (n=20).

Source

Effects of caffeine on energy metabolism, heart rate, and methylxanthine metabolism in lean and obese women

David Bracco et al. · American Journal of Physiology-Endocrinology and Metabolism · 1995

DOI 10.1152/ajpendo.1995.269.4.e671

crossover · n=20Cited 181×
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DOI resolved against Crossref · corpus check 2026-06-10

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