What is Thermic Effect of Food (TEF)?
The thermic effect of food (TEF), also called diet-induced thermogenesis (DIT) or specific dynamic action (SDA) is the energy cost of digesting, absorbing, and storing nutrients.
A TEF calculator helps estimate how much of your daily calorie needs go toward digestion.
On average, TEF accounts for roughly 8–12% of total calorie intake, but it shifts with macronutrient composition, food processing, and overall intake. TEF tends to be higher with higher protein intake and can shift during overfeeding or dieting.
Typical TEF ranges by macro
- Protein: roughly 20–30% of protein calories used during digestion.
- Carbohydrates: roughly 5–10% of carb calories.
- Fat: roughly 0–3% of fat calories.
- Mixed meals land between those ranges depending on protein share and total intake.
What TEF is not
- TEF is not “free calories”
- TEF differences matter, but they’re usually smaller than tracking error
- TEF won’t “offset” overeating in a meaningful way
TEF calculation example
To estimate TEF from total calorie intake and macro split, multiply each macro’s calories by its TEF rate and sum the results:
- Protein calories × 25%
- Carb calories × 10%
- Fat calories × 3%
Example: a 2,000 kcal/day diet with 150g protein (600 kcal), 200g carbs (800 kcal), and 78g fat (700 kcal):
- Protein: 600 kcal × 25% = 150 kcal
- Carbs: 800 kcal × 10% = 80 kcal
- Fat: 600 kcal × 3% = 18 kcal
Total TEF = 150 + 80 + 18 = 248 kcal/day
How TEF is calculated
When you log manual activity calories, the calculator lets you choose a fixed TEF percentage or a macro-weighted
model based on your macro split.
If you use an activity multiplier (PAL),
TEF is already baked into that factor. Many TDEE multipliers were derived from real-world energy
expenditure, which typically includes digestion. To keep results comparable and avoid counting digestion twice,
we use a standard TEF assumption (10%) when PAL is selected and show it
as a separate line item.
TEF is an estimate, not a lab measurement. It varies with protein intake, meal size, food quality, and energy balance, so treat the result as a helpful range rather than a single exact number.
Fixed percentage
Simple and predictable. Choose a percentage (commonly 8–12%) and we apply it to your daily calorie intake to estimate calorie burn from digestion. Use this when you do not have reliable macro data or when you need to mirror legacy TEF calculator settings that hardcode the thermic effect of food.
Macro-weighted
Protein costs more calories to digest than carbs or fat. When macro-weighted TEF is selected we ask for your macro split as percentages (protein, carbs, fat) that sum to 100% (example: 30% protein / 40% carbs / 30% fat). Those percentages let the calculator weight TEF using standard thermic ranges (25% protein, 7.5% carbs, 2% fat). Macro percentages are a simplification — TEF also depends on total intake and food quality.
- High-protein plans show higher TEF and slightly lower net calories.
- High-fat plans show lower TEF because fat digestion is more efficient.
- You can still switch back to fixed mode any time—results only update after pressing Calculate.
Tips
- Use macro-weighted TEF when comparing macro splits or reconciling macro coaching feedback.
- Match the macro percentages to your plan; adjust them as your nutrition changes.
- Revisit your TEF settings after big shifts in protein intake or total calories.
Ready to experiment? Switch the calculator’s Physical Activity mode to manual, adjust TEF methods, and rerun a calculation. When you prefer PAL multipliers, the thermic effect of food stays implicit in that factor.