Digestion Is Metabolically Expensive Total daily energy expenditure has four components: basal metabolic rate (the calories your body burns at rest — typically 60–70% of TDEE), non-exercise activity thermogenesis (movement outside formal exercise — 15–30%), exercise thermogenesis (formal training — typically 5–10%), and the thermic effect of food (TEF) — the calories burned in the process of digesting, absorbing, and metabolising what you eat. TEF accounts for approximately 10% of total daily energy expenditure in people eating a typical Western diet. 10% sounds modest. But the a…