Understanding BMR and TDEE
The Energy Equation
Weight management fundamentally comes down to energy balance: Calories In vs. Calories Out. To manage this effectively, you need to understand two key numbers.
1. Basal Metabolic Rate (BMR)
What is it? BMR is the number of calories your body burns just to stay alive—breathing, circulating blood, cell production, etc.—while at complete rest.
Why it matters: This is your baseline. Even if you stayed in bed all day, you would burn this amount. Eating below your BMR is generally not recommended as it can slow down your metabolism.
2. Total Daily Energy Expenditure (TDEE)
What is it? TDEE is your BMR plus the calories you burn through physical activity (exercise + daily movement) and the thermic effect of food.
Why it matters: This is your maintenance level.
- To Lose Weight: Eat below your TDEE (Calorie Deficit).
- To Gain Weight: Eat above your TDEE (Calorie Surplus).
- To Maintain: Eat at your TDEE.
Calculating Your Needs
Most calculators use formulas like the Mifflin-St Jeor equation to estimate BMR, then multiply it by an "activity factor" (e.g., 1.2 for sedentary, 1.55 for moderate exercise) to find TDEE.