Do you burn calories digesting food? Set your day's mix and see how much

Calories eaten in a day (an example, not a target) 2000 kcal

Protein, share of calories 20%

Fat, share of calories 30%

Where your calories come from: P protein, C carbs, F fat (carbs fill the rest)

about 180 kcal of 2000

The slice your body spends on digesting (drawn to scale)

Nutrient	Grams	kcal	Used to digest

Estimate = protein kcal × 20–30% + carb kcal × 5–10% + fat kcal × 0–3%, using 4 kcal per gram of protein and carbs and 9 per gram of fat. The bar and the big number use the middle of each range. Real bodies differ, and so do meals.