What is the difference between BMR and TDEE?

BMR (Basal Metabolic Rate) is the amount of energy your body burns at complete rest to maintain vital functions. TDEE (Total Daily Energy Expenditure) includes BMR plus all physical activity and the thermic effect of food. TDEE is the number used to calculate your calorie budget — to lose weight, you need to eat less than your TDEE.

Should you ever eat below your BMR?

Long-term eating below your BMR is not recommended. It slows down metabolism, leads to muscle mass loss, fatigue, and nutrient deficiencies. Short-term eating below BMR may be safe under medical supervision, but lasting results come from a moderate 300–500 kcal deficit from TDEE.

Why does basal metabolic rate decrease with age?

Basal metabolic rate decreases with age primarily due to loss of muscle mass. After age 30, muscle mass decreases by about 3–5% per decade without strength training. Since muscle mass is metabolically active tissue, its reduction lowers BMR. Strength training can significantly slow down this process.

How accurately does the BMR calculator estimate my expenditure?

The Mifflin-St Jeor formula has been found to be the most accurate BMR estimation method in studies, but even it has a margin of error of about 10%. Individual differences in genetics, hormone levels, and body composition affect actual expenditure. Use the result as a starting point and adjust calories based on weight changes after a 2–3 week monitoring period.

BMR & TDEE Calculator — Calculate Your Basal Metabolic Rate

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What do BMR and TDEE mean?

BMR (Basal Metabolic Rate) is the amount of energy your body burns at rest to maintain vital functions: breathing, circulation, and cell renewal. It accounts for 60–70% of daily energy expenditure.

TDEE (Total Daily Energy Expenditure) adds exercise and daily activity to BMR. Eating less than your TDEE creates a calorie deficit, which leads to weight loss.

A moderate 500 kcal daily deficit produces about 0.5 kg of weight loss per week. You should not eat below your BMR long-term.

Related terms

BMR TDEE Calorie Deficit Metabolism

Frequently Asked Questions about BMR and TDEE

Disclaimer: This page contains general health and wellness information and does not replace the advice of a doctor, dietitian, or other healthcare professional. Always consult your doctor before making significant changes to your diet or exercise routine, especially if you have underlying health conditions, are on medication, or are pregnant.

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