Key facts
- One of the components of your TDEE.
- Protein has the highest thermic effect (20–30%).
- Carbs are moderate (5–10%); fat is lowest (0–3%).
- Roughly 10% of total daily calories for a mixed diet.
Digesting food isn't free — it costs energy. The thermic effect of food is the calories burned breaking down and processing what you eat, and it makes up roughly 10% of your total daily energy expenditure for a typical mixed diet.
Protein has by far the highest thermic effect: 20–30% of its calories are used just to process it, compared with 5–10% for carbs and almost nothing for fat. This is one reason higher-protein diets are slightly favorable for fat loss — a small extra calorie cost on top of protein's satiety and muscle-preserving benefits.
Frequently asked questions
Which foods have the highest thermic effect?
Protein has the highest thermic effect, using 20–30% of its calories to digest, versus 5–10% for carbs and roughly 0–3% for fat.
Can I boost metabolism through TEF?
Modestly. Eating more protein raises TEF slightly, but the effect is small — it's a minor bonus alongside protein's bigger benefits for satiety and muscle.
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