BMR vs TDEE: The Two Numbers That Control Your Weight
BMR is what your body burns at rest. TDEE is what you actually burn all day. Understanding both is the key to any diet.
Your Basal Metabolic Rate (BMR) is the calories your body needs to keep you alive while doing absolutely nothing — breathing, pumping blood, maintaining body temperature, running your brain. For most adults, BMR is 1,400-2,000 calories per day. You should never eat below your BMR.
TDEE = BMR × Activity
Your Total Daily Energy Expenditure is BMR multiplied by an activity factor: sedentary (×1.2), lightly active (×1.375), moderately active (×1.55), very active (×1.725). A person with a 1,700 BMR who exercises 3-5 days per week: 1,700 × 1.55 = 2,635 TDEE. Eat 2,635 to maintain weight. Eat 2,135 to lose about 1 pound per week. Eat 3,135 to gain about 1 pound per week.
Why Diets Fail
Most people underestimate calories consumed by 30-50% and overestimate calories burned by 20-40%. When your estimated deficit does not produce weight loss, the math is wrong — not your metabolism. Track food with a kitchen scale for 2 weeks to calibrate your awareness, then you can estimate accurately going forward.