Thermic Effect of Food Calculator

📚 Full explanation

Thermic Effect of Food (TEF): the “hidden” calories you burn by eating

The Thermic Effect of Food (TEF) is the energy your body spends to digest, absorb, transport, and store the nutrients you eat. It’s sometimes called diet-induced thermogenesis. If you’ve ever heard someone say “protein burns more calories to digest,” they’re talking about TEF.

TEF doesn’t mean food has “negative calories.” It means your body’s metabolism rises a little after a meal, because breaking food down and processing it takes work. For most people, TEF contributes roughly 5–15% of total daily energy expenditure depending on diet composition, meal size, and individual factors. If you’re tracking calories for weight loss, maintenance, or a lean-bulk, TEF is one of the reasons two diets with the same calorie total can feel slightly different in real life.

Why this calculator is useful

Meal-level clarity: Estimate how many calories your body burns processing a specific meal.
Macro awareness: See how protein vs carbs vs fat changes TEF, even when calories are similar.
Planning: Combine TEF insights with TDEE, deficit/surplus planning, or macro targets.
Virality: Share a “meal TEF” screenshot (especially for high-protein meals) and compare with friends.

How TEF works (plain-English version)

When you eat, your body does several energy-d emanding tasks: chewing and swallowing, producing stomach acid, releasing digestive enzymes, absorbing nutrients through the gut wall, transporting them in blood, converting them into usable forms, and storing them (glycogen, fat, muscle repair, etc.). Those processes require ATP (energy), so your metabolic rate rises for a few hours after eating. That rise is TEF.

TEF varies by macronutrient:

Protein: typically the highest TEF because protein is costly to break down and rebuild into body proteins.
Carbs: moderate TEF; digestion is easier than protein but still requires processing.
Fat: usually the lowest TEF; fats are energy-dense and more efficient to store.
Alcohol (optional): has a noticeable processing cost in many estimates, so we include it as optional.

Formula breakdown (the exact math used here)

This calculator uses a macro-based TEF estimate. That means we: (1) convert your macro grams into calories, (2) apply a TEF percentage for each macro, and (3) add them up.

Step 1: Convert grams → calories

Protein calories = protein grams × 4
Carb calories = carb grams × 4
Fat calories = fat grams × 9
Alcohol calories (optional) = alcohol grams × 7

Step 2: Apply TEF rates

TEF is estimated as a fraction of each macro’s calories. We show a best estimate plus a range. The default “best estimate” rates we use are:

Protein TEF: 25% (range 20–30%)
Carb TEF: 7.5% (range 5–10%)
Fat TEF: 2% (range 0–3%)
Alcohol TEF: 10% (simple estimate)

Step 3: Add it up

TEF calories = (protein calories × protein TEF) + (carb calories × carb TEF) + (fat calories × fat TEF) + (alcohol calories × alcohol TEF)
TEF % of meal = TEF calories ÷ meal calories × 100

Examples (real numbers)

Example 1: High-protein meal

Protein: 50g → 200 kcal
Carbs: 40g → 160 kcal
Fat: 15g → 135 kcal
Total: 495 kcal

Estimated TEF = (200×0.25) + (160×0.075) + (135×0.02) = 50 + 12 + 2.7 = ~64.7 kcal. TEF% ≈ 64.7/495 = ~13.1%.

Example 2: Higher-fat meal (same calories)

Protein: 25g → 100 kcal
Carbs: 35g → 140 kcal
Fat: 28g → 252 kcal
Total: 492 kcal

Estimated TEF = (100×0.25) + (140×0.075) + (252×0.02) = 25 + 10.5 + 5.0 = ~40.5 kcal. TEF% ≈ 40.5/492 = ~8.2%.

Example 3: Carb-heavy snack

Protein: 5g → 20 kcal
Carbs: 60g → 240 kcal
Fat: 5g → 45 kcal
Total: 305 kcal

Estimated TEF = (20×0.25) + (240×0.075) + (45×0.02) = 5 + 18 + 0.9 = ~23.9 kcal. TEF% ≈ 23.9/305 = ~7.8%.

How to use TEF in real life (without overcomplicating it)

TEF is real — but it’s also not a magic hack. The smartest way to use TEF is as a planning nudge, not a reason to micromanage your numbers. Practical uses:

Protein-first meal planning: higher protein often improves satiety and slightly increases TEF.
Comparing meal options: same calories, different macros → different TEF estimate.
Diet consistency: TEF is one reason high-protein diets can feel easier during a deficit.
Education: TEF explains why macros matter beyond calories.

TEF is most helpful when paired with bigger levers: total calorie intake, consistent training, sleep, daily steps, and weekly adherence. Think of TEF like the “fine-tuning dial,” not the “engine.”

What changes TEF (and why your result is a range)

TEF varies across people and situations. This calculator shows a range because TEF can shift with:

Meal size: bigger meals generally create a bigger absolute TEF.
Food processing: whole foods can be more costly to digest than ultra-processed foods.
Fiber: higher fiber can raise digestive effort in some contexts.
Training status: muscle and recovery needs can influence overall energy use.
Sleep/stress: affect appetite and energy balance in ways that matter more than small TEF differences.

FAQ

Is TEF the same as metabolism?
TEF is one piece of daily energy expenditure, alongside BMR, activity, and exercise.
What TEF% is “good”?
There’s no best number. Mixed diets often land around 8–12% of intake; high-protein meals can be higher.
Does meal frequency change TEF?
Total TEF is driven more by total intake and macro mix than by how many meals you split it into.
Can I lose weight just by increasing TEF?
TEF alone is usually too small to drive results, but higher protein can help with satiety and adherence.
Why include alcohol?
Alcohol adds calories and has processing costs. Including it helps estimate TEF for real-life meals and drinks.
Is this medically accurate?
It’s an educational estimate. If you have conditions affecting digestion/metabolism, consult a clinician.

Educational use only. TEF estimates vary by individual, food processing, and measurement error. For goals like weight loss or performance nutrition, use TEF as a helpful guide — not a strict rule.