What Is My BMR? The Metabolism Number You Can't Ignore
Your metabolism isn't just one thing. It's a collection of processes that keep you alive, and the biggest chunk of it—about 70%—is your **Basal Metabolic Rate (BMR)**.
Understanding your BMR is the key to understanding why some people seem to eat whatever they want while others struggle. In this guide, we'll break down the science of BMR and how you can influence it.
What Exactly Is BMR?
BMR stands for **Basal Metabolic Rate**. It represents the number of calories your body burns at complete rest. Imagine you laid in bed all day, didn't move, didn't think hard, and didn't even digest food. The energy your body would use just to keep your heart beating, lungs breathing, and cells dividing is your BMR.
Essentially, it's the 'operating cost' of your body.
BMR vs. TDEE: What's the Difference?
This is a common point of confusion. **BMR** is what you burn at rest. **TDEE (Total Daily Energy Expenditure)** is what you burn in total, including movement and exercise.
- •**BMR**: The floor. You should almost never eat below this number.
- •**TDEE**: The ceiling. This is your maintenance level.
What Determines Your BMR?
Your BMR isn't random. It's determined by four main factors:
- 1**Body Size**: Larger bodies have more cells to maintain, so they have higher BMRs. A 6'4" man has a much higher BMR than a 5'2" woman.
- 2**Body Composition**: Muscle burns more calories than fat. Two people can weigh 200 lbs, but the one with 10% body fat will have a significantly higher BMR than the one with 30% body fat.
- 3**Age**: BMR generally peaks in your early 20s and declines by 1-2% per decade as muscle mass naturally decreases.
- 4**Gender**: Men typically have less body fat and more muscle mass than women of the same weight, leading to a higher BMR.
Can You Increase Your BMR?
Yes! While you can't change your age or height, you absolutely can change your body composition. **Building muscle** is the most effective way to raise your BMR.
Every pound of new muscle you build requires energy to maintain. While the '50 calories per pound of muscle' stat is a myth (it's closer to 6-10 calories), the comprehensive effect of resistance training—including the 'afterburn' effect and hormonal improvements—makes weightlifting the best metabolic booster available.
Conclusion
Don't starve yourself. Eating below your BMR is a recipe for disaster. Instead, calculate your BMR to find your baseline, then use movement and muscle-building to push your total burn higher. That is the sustainable path to a better physique.