BMR & Weight Management — Your Metabolic Baseline

What Is BMR?

BMR stands for Basal Metabolic Rate. It's the number of calories your body burns at complete rest — just breathing, circulating blood, repairing cells, and keeping your temperature stable. It accounts for a massive **60–75%** of your total daily calorie burn.

By comparison, exercise and walking make up only **10–30%**. That's why knowing your BMR is the foundation of any weight management plan.

BMR vs. TDEE — What's the Difference?

Your Total Daily Energy Expenditure (TDEE) is BMR plus everything else: the thermic effect of food (digestion burns about 10% of your calories), NEAT (non-exercise activity like fidgeting and walking), and deliberate exercise. To get your TDEE, multiply your BMR by an activity factor: **1. 2** for sedentary, **1.

55** for moderate exercise, up to **1. 9** for active. Your TDEE is the real number for weight management — BMR is just the starting point.

The Mifflin-St Jeor equation is the most accurate formula for estimating BMR in the general population.

How to Use BMR for Weight Loss

To lose weight, you need a calorie deficit — eating fewer calories than your TDEE. But here's the critical rule: never eat below your BMR. Doing so forces your body to break down muscle and organ tissue for fuel.

A safe deficit's **250–500 calories below TDEE**, which yields about **0. 5–1 lb of fat loss per week**. Women shouldn't go below **1,200 calories** daily, and men shouldn't go below **1,500**, unless medically supervised.

Does Your BMR Change With Age?

Yes. BMR drops about **2% per decade** after age 20. That's roughly 20–30 fewer calories burned per day each decade.

The primary cause isn't aging itself — it's sarcopenia, the gradual loss of muscle mass. The good news? Resistance training is the most effective way to slow or even reverse this decline.

Muscle tissue burns about **6 calories per pound per day** at rest, while fat tissue burns only about 2.