The number of calories your body burns at complete rest, the foundation of every nutrition plan.
Mifflin-St Jeor, the gold standard for BMR
Basal Metabolic Rate (BMR) is the energy your body uses to keep you alive at complete rest, pumping blood, breathing, maintaining temperature, repairing cells, supporting brain activity. For most adults it accounts for 60-75% of total daily calorie burn.
We use the Mifflin-St Jeor equation, which the Academy of Nutrition and Dietetics endorses as the most accurate predictive formula for resting metabolism in healthy non-obese and obese adults.
Your BMR is a calorie floor, not a target. Eating consistently below it triggers metabolic adaptations: lowered thyroid output, increased cortisol, muscle loss and stalled weight loss.
Two practical takeaways:
For weight gain specifically, BMR is critical, many underweight adults are unknowingly eating barely above BMR, which keeps the body in conservation mode and prevents any gain. The fix is structured, energy-dense meals built around a TDEE target, not just BMR.
See our healthy weight gain program for a structured approach, or read our healthy weight gain guide.
This calculator is most useful if you're working on:
Nutrient-dense plans for lean, healthy weight and muscle gain.
Diet plans for hypothyroidism and hyperthyroidism management.
BMR tells you where the floor is, a personalised plan tells you how to build above it without overshooting. Book a free consultation to map it out.
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