TEF Calculator
Calculate how many calories your body burns digesting food
Your TEF Results
Track Your TEF Automatically
AI Food Coach calculates your thermic effect dynamically from every meal you log — not a flat estimate.
What is the Thermic Effect of Food?
The Thermic Effect of Food (TEF), also known as diet-induced thermogenesis (DIT), is the energy your body expends to digest, absorb, transport, and metabolize the nutrients in your food. It’s one of three components of your total daily energy expenditure (TDEE), alongside your Basal Metabolic Rate (BMR) and physical activity.
TEF typically accounts for 5–15% of your total calorie intake. The exact percentage depends primarily on the macronutrient composition of your diet — not the total calories. A 2,000 kcal high-protein diet burns significantly more through TEF than a 2,000 kcal high-fat diet.
TEF by Macronutrient
Each macronutrient requires a different amount of energy to process, so your macro ratio changes how much of your calories digestion uses:
| Macronutrient | Thermic Effect | Research Range | Why |
|---|---|---|---|
| Protein | 20–30% | Westerterp 2004 | Amino acid processing, gluconeogenesis, urea synthesis |
| Carbohydrates | 5–10% | Westerterp 2004 | Glycogen conversion, insulin response, glucose transport |
| Fat | 0–3% | Westerterp 2004 | Minimal processing needed — dietary fat is already close to storage form |
| Alcohol | 10–30% | Westerterp 2004 | Detoxification priority in liver, inefficient metabolism |
Protein has the highest thermic effect because your body must break peptide bonds, convert amino acids, synthesize new proteins, and convert excess to glucose through gluconeogenesis. This process is energetically expensive — your body uses 20–30% of protein’s calories just to process it.
How to Increase Your TEF
Since TEF is determined by what you eat, you can influence it through dietary choices:
- Increase protein intake: Swapping 100 kcal of fat for 100 kcal of protein burns ~22 extra calories through TEF alone. Over a year, that adds up.
- Eat whole foods: In a 2010 study (Barr & Wright) of 17 adults, a sandwich of multi-grain bread and cheddar raised energy expenditure by 137 kcal, an equal-calorie sandwich of white bread and processed cheese by 73 kcal — nearly twice as much for the whole-food meal.
- Don’t worry about meal timing: Whether you eat 2 or 6 meals per day, your total daily TEF is the same — it depends on total macros consumed, not meal frequency.
The single most impactful change is increasing protein. A shift from 15% to 30% protein can increase daily TEF by 60–100 kcal — equivalent to a 20-minute walk.
TEF and Weight Loss
TEF creates “free” calorie burn — energy your body uses just processing the food you already eat. While individual meals have small TEF differences, the cumulative effect across months is meaningful:
Real-world example: A high-protein diet (30% protein, 40% carbs, 30% fat) at 2,000 kcal produces ~225 kcal/day TEF. A high-fat diet (15% protein, 35% carbs, 50% fat) at 2,000 kcal produces only ~153 kcal/day TEF. That’s a ~72 kcal/day difference — or about 3.4 kg of body weight per year, all else being equal.
High-protein diets can help with weight control in two ways: protein is filling, and your body burns more calories processing protein-rich foods (Westerterp 2004).
Most calorie trackers ignore TEF or use a flat 10% estimate. AI Food Coach calculates TEF dynamically from your actual macros, giving you a more accurate calorie target that accounts for this hidden calorie burn.
Our Formula
This calculator uses midpoint values from peer-reviewed research to estimate TEF per macronutrient:
The coefficients (25%, 7.5%, 2.5%) are the short-term thermic effects of protein, carbohydrate and fat used in Hall’s model of human metabolism, and they sit within the ranges of Westerterp’s review (20–30%, 5–10%, 0–3%). These values come from:
- Hall KD (2010) — “Predicting metabolic adaptation, body weight change, and energy intake in humans.” Am J Physiol Endocrinol Metab.
- Westerterp KR (2004) — “Diet induced thermogenesis.” Nutr Metab.
For a complete overview of how AI Food Coach uses these calculations, see our methodology and sources page.
