Thermic Effect of Food Calculator

What the Thermic Effect of Food Calculator Does

Your body burns calories just digesting the food you eat, a cost known as the thermic effect of food. This calculator estimates how many calories that digestion costs you each day. Dietitians use it when building meal plans, and fitness enthusiasts use it to reconcile their TDEE with real world results.

The average person loses about 10 percent of daily calories to digestion, but the share swings with macro choices. Protein is the most expensive macronutrient to process, so high protein eaters see a noticeably bigger burn.

How TEF Is Calculated

The simplest method multiplies total daily calories by 0.1, so 2000 calories eaten means roughly 200 calories spent on digestion. The calculator goes further by weighing each macro: protein burns 20 to 30 percent of its calories, carbohydrates 5 to 10 percent, and fat just 0 to 3 percent.

Example: enter 150 grams of protein, 200 grams of carbs, and 70 grams of fat. That converts to 600, 800, and 630 calories. Applying 25, 7.5, and 1.5 percent gives roughly 150, 60, and 9 calories, so digestion costs about 220 calories that day.

Using the Calculator and Reading the Result

Type your daily grams into the Carbohydrates, Proteins, and Fats fields; the Percentages and Proportions buttons switch how the macro split is expressed. Total Intake and TDEE are optional fields that give the tool extra context. Weigh macros across a full day, not a single meal, because TEF only paints a useful picture in daily terms.

A high protein diet can push TEF toward 15 percent of intake, while a fat heavy one drags it near 5 percent. Recalculate whenever your macro split shifts substantially. Track your weight trend for two weeks to confirm the estimate matches reality.