Why BMR falls as you lose weight
A smaller body costs less to run. Every 10 lb lost trims roughly 40–70 kcal off daily resting burn, which is why a deficit that worked in month one stalls by month four. Recalculating every 10–15 lb keeps the plan honest.
- • Resistance training preserves lean mass, the tissue that keeps BMR high.
- • Very low calorie intake can suppress BMR beyond what weight loss alone predicts.
- • Sleep debt and chronic stress both reduce measured resting expenditure.
FAQ
What is the difference between BMR and RMR?
BMR is measured after an overnight fast in a fully rested state; RMR is measured under less strict conditions and typically comes out 5–10% higher. In practice the two are used interchangeably.
Should I eat at my BMR to lose weight?
No. BMR is the floor for keeping your body running at rest. Weight loss plans target a deficit against total daily burn (TDEE), which is always higher than BMR.
How accurate is the Mifflin-St Jeor formula?
It lands within 10% of measured resting expenditure for about 70% of people. Very muscular or very high body-fat individuals see larger errors.
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