Glossary · Definition
RMR (Resting Metabolic Rate)
RMR (Resting Metabolic Rate) is the calories your body burns at rest in 24 hours just to maintain basic functions — heart, brain, organs. Foundation for setting weight-loss or weight-gain calorie targets.
Definition
RMR (Resting Metabolic Rate) is the calories your body burns at rest in 24 hours just to maintain basic functions — heart, brain, organs. Foundation for setting weight-loss or weight-gain calorie targets.
What it means
Most-used estimate is the Mifflin-St Jeor equation: men = 10×weight(kg) + 6.25×height(cm) - 5×age + 5; women = same minus 161. Adult RMR typically 1,400-2,000 kcal/day depending on body size + composition. To get total daily energy expenditure (TDEE), multiply RMR by an activity factor (1.2 sedentary to 1.9 very active).
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Why it matters
RMR is the floor for calorie planning. To lose weight, eat below TDEE; to gain, eat above. Most weight-loss plans target a 500 kcal/day deficit, producing roughly 1 lb/week loss. RMR drops during prolonged caloric deficit (adaptive thermogenesis) — the body adapts.
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Frequently asked questions
How accurate is the formula?
Within ±15% for most people. Body composition heavily affects accuracy — high muscle = higher RMR than the formula predicts; high fat % = lower.
How do I measure RMR directly?
Indirect calorimetry (a metabolic cart, ~$100-200 at sports clinics). Most accurate; not necessary for most people.