Thermic Effect of Food (TEF)
The metabolic energy cost required to chew, digest, absorb, transport, and metabolize ingested nutrients.
Clinical & Bioenergetic Overview
Thermic Effect of Food (TEF), also known as Diet-Induced Thermogenesis (DIT), is the energetic expenditure associated with nutrient assimilation. Different macronutrients have radically different metabolic processing overheads: dietary protein demands 20% to 30% of its caloric value to metabolize, carbohydrates consume 5% to 10%, and dietary fats require merely 0% to 3%.
Mathematical Formula & Calculation
Real-World Worked Example
Consuming 200g of chicken breast (~220 kcal of pure protein) requires approximately 55 kcal simply to denature, hydrolyze, and enzymatically process the peptide bonds into free amino acids, leaving a net absorbed yield of ~165 kcal.
Why It Matters for Dieting
Elevating dietary protein to 30%-35% of total caloric intake significantly amplifies 24-hour TEF, burning up to 100-150 extra calories per day through digestion alone compared to an isocaloric high-fat diet.
Frequent Mistakes
Believing that eating six small meals a day "stokes the metabolic fire." Clinical trials demonstrate that total 24-hour TEF is identical whether a given amount of food is eaten across 2 meals or 6 meals.
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Optimize your protein intake to maximize metabolic thermogenesis.
Related Bioenergetic Terms
The total cumulative number of kilocalories your body burns over a 24-hour cycle across all metabolic components.
The relative caloric distribution of protein, carbohydrate, and fat consumed within a daily diet.
The biochemical process of incorporating dietary amino acids into bound skeletal muscle contractile tissue.