Estimate the Thermic Effect of Food, the calories your body burns digesting your meals, from your daily protein, carbs, and fat.
TEF stands for the thermic effect of food, the calories your body spends digesting, absorbing and processing what you eat. It is the quiet third component of your daily energy burn, alongside your resting metabolism and your activity. This calculator estimates your daily TEF from the protein, carbs and fat you eat, and shows how much each macronutrient contributes.
I think TEF is one of the most underappreciated reasons that protein is so useful for body composition. You do not get a huge metabolic bonus from food, but the differences between macronutrients are real, and over months they add up in a direction that favors higher-protein eating.
Not all calories cost the same to process. Protein has by far the highest thermic effect: roughly 20 to 30% of its calories are used up just digesting and metabolizing it, partly because building and breaking down amino acids is metabolically expensive. Carbohydrates sit around 5 to 10%, and fat is the cheapest to store at roughly 0 to 3%. This calculator uses mid-range values (25% protein, 7.5% carbs, 2% fat) to give a balanced estimate.
For a typical mixed diet, TEF accounts for around 10% of your total daily energy expenditure. It is meaningful but modest, so it will not outrun a poor overall diet. Where it earns its keep is at the margins: shifting calories toward protein raises your TEF a little, helps with fullness, and protects muscle, which together make a higher-protein approach genuinely useful for fat loss.
Treat your TEF as part of the explanation for why protein helps, not as a calorie loophole to exploit. The practical takeaway is simple: build meals around a solid protein source, include fiber-rich whole foods, and do not obsess over the exact figure. The combined effect of better satiety, muscle retention and a slightly higher thermic cost is what matters, far more than any single day's TEF total.
This calculator uses established, peer-reviewed formulas and reference ranges from recognized health and nutrition authorities. Results are estimates for general education, not a medical diagnosis. For decisions about your health, consult a qualified clinician. Reviewed by Jennifer Zoned, PhD, Nutrition Researcher.
TEF is the energy your body uses to digest, absorb and process the food you eat. It is one of the three parts of your daily calorie burn, along with your resting metabolism and physical activity, and it typically accounts for around 10% of total daily energy expenditure on a mixed diet.
Protein is metabolically expensive to process. Roughly 20 to 30% of protein calories are used up during digestion and metabolism, compared with about 5 to 10% for carbohydrates and 0 to 3% for fat. This is one reason higher-protein diets can gently support fat loss and muscle retention.
Not meaningfully. TEF is proportional to the total amount and type of food you eat, not how many times you eat it. Splitting the same calories across more meals gives you smaller TEF bumps more often, but the daily total is about the same, so meal frequency is mostly a matter of personal preference.
Only at the margins. TEF is real but modest, so it will not override your overall calorie balance. The useful move is shifting some calories toward protein, which raises TEF a little while improving fullness and protecting muscle. Treat it as a helpful nudge, not a shortcut.
