Catechins

Foods that genuinely affect metabolic rate do so through two mechanisms: thermic effect (the energy cost of digestion) and thermogenesis (heat production that increases energy expenditure). Protein has by far the largest thermic effect of any macronutrient. Other foods — capsaicin, caffeine, catechins — have small, transient effects that do not translate to meaningful weight loss without a calorie deficit.

Green tea contains two bioactive compounds — EGCG and caffeine — with documented effects on energy expenditure and fat oxidation. This article examines the mechanism, the quantified effect from clinical trials, and the conditions under which any benefit applies.

Foods that support metabolic health work through specific, distinct mechanisms. This article maps individual foods to their evidence-based metabolic effects — thermic effect, thermogenesis, satiety hormone stimulation, insulin sensitivity, and lean mass support — with quantified effect sizes.