Your TDEE (Total Daily Energy Expenditure) is the single most important number for weight loss. It tells you exactly how many calories your body burns each day — and once you know it, creating a calorie deficit becomes straightforward math.
What is TDEE?
TDEE is the total number of calories you burn in a 24-hour period. It includes three components:
- BMR (Basal Metabolic Rate): Calories burned at complete rest — breathing, circulation, cell repair. This accounts for 60-70% of your TDEE.
- TEF (Thermic Effect of Food): Energy used to digest food. About 10% of your TDEE.
- Activity: Everything from walking to the gym to fidgeting. The most variable component.
Step 1: Calculate Your BMR
The most accurate formula for estimating BMR is the Mifflin-St Jeor equation, which uses your weight, height, age, and sex:
- Men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
- Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161
Step 2: Multiply by Your Activity Factor
Your BMR is then multiplied by an activity factor to estimate your TDEE:
- Sedentary (desk job, little exercise): BMR × 1.2
- Lightly active (exercise 1-3 days/week): BMR × 1.375
- Moderately active (exercise 3-5 days/week): BMR × 1.55
- Very active (exercise 6-7 days/week): BMR × 1.725
- Extra active (hard exercise + physical job): BMR × 1.9
Or skip the math entirely — use our TDEE calculator to get your number in seconds.
Step 3: Create Your Deficit
Once you know your TDEE, weight loss is simple: eat fewer calories than you burn.
- 500 cal/day deficit = ~1 lb/week loss
- 750 cal/day deficit = ~1.5 lb/week loss
- 1000 cal/day deficit = ~2 lb/week loss (aggressive — not recommended long-term)
Use our calorie deficit calculator to see exactly how many calories to eat and how long it will take to reach your goal weight.
Common Mistakes
- Overestimating activity level. Most people should start with "lightly active" even if they exercise regularly. Adjust up if you're losing faster than expected.
- Not recalculating. As you lose weight, your TDEE drops. Recalculate every 10-15 lbs.
- Cutting too aggressively. Never go below 1,200 calories without medical supervision. Large deficits lead to muscle loss, fatigue, and metabolic adaptation.
- Ignoring protein. In a deficit, high protein intake (1.6-2.2g per kg) helps preserve muscle. Calculate your protein needs.
Putting It All Together
Here's the recommended flow:
- Calculate your TDEE
- Set your calorie deficit
- Plan your macros
- Track your food for 2 weeks, then adjust based on real-world results
The math gets you 90% of the way there. The last 10% is consistency.