Calculation of TDEE

TDEE vs BMR: the difference

The BMR (Basal Metabolic Rate) is the energy that your body consumes at absolute rest — vital functions only. The TDEE (Total Daily Energy Expenditure) also includes all your daily activity: work, walking, sport, household. This is the real calorie target to control your diet.

Formula: TDEE = BMR × activity factor

Activity factors explained

Factors are statistical averages. It is better to underestimate your activity (start with “lightly active” rather than “very active”) and adjust according to the results observed over 2-3 weeks.

• Sedentary (×1.2): office, no sport. Walk < 30 min/day.
• Lightly active (×1,375): 1-3 light sports sessions per week.
• Moderately active (×1.55): 3-5 moderate sports sessions per week.
• Very active (×1,725): 6-7 sustained sessions + daily activity.
• Extremely active (×1.9): intensive daily sport (athlete) or physical profession (construction, mover).

Method used — Mifflin-St Jeor

We use the Mifflin-St Jeor (1990) formula for BMR, considered the most accurate for the general population by the Academy of Nutrition and Dietetics:

• Men: BMR = (10 × weight) + (6.25 × height) − (5 × age) + 5
• Women: BMR = (10 × weight) + (6.25 × height) − (5 × age) − 161

What to do with your TDEE

Once your TDEE is known, three main uses:

1. Weight loss — calorie deficit

Eat below your TDEE. Recommended moderate deficit: 300-500 kcal/day. Faster is not better: losing too aggressively (> 1% of weight/week) damages muscle mass and slows down metabolism. See calorie deficit.

2. Muscle gain — calorie surplus

Eat above your TDEE. Moderate surplus: 200-300 kcal/day. Beyond that, you mainly gain fat. With strength training and 1.6-2 g/kg of protein, expect +1-2 kg of pure muscle per year in an intermediate.

3. Maintenance — energy balance

Eat at your TDEE. This is useful in the stabilization phase after drying or before setting. Also allows you to “reset” the metabolism before a new phase.

Precision and margin of error

The estimated TDEE has a margin of ±10-15% compared to your actual expenditure. The causes:

• Actual body composition (muscle burns more than fat at rest)
• Genetics of metabolism
• Hormonal state (thyroid, cortisol)
• NEAT (Non-Exercise Activity Thermogenesis): fidgeting, climbing stairs, varies enormously between individuals

The only way to have an accurate TDEE is to adjust for observation: if you eat at your estimated TDEE for 2 weeks and your weight goes up, your true TDEE is lower than the estimate. Conversely if it falls.

Go further

Once your TDEE is known, you can:

• Calculate your macros (proteins, carbohydrates, lipids)
• Calibrate your deficit or surplus
• Estimate your protein needs
• Follow the evolution with your BMI and your fat mass rate