Estimate daily caloric needs with the Cunningham equation, which bases resting metabolic rate (RMR) on lean body mass rather than total weight alone. It is often preferred for athletes and individuals with known body-fat percentage.
Formula (RMR)
RMR = 500 + 22 × lean body mass (kg)
Lean body mass = weight × (1 − body fat % ÷ 100). Enter weight, height, age, sex, and body-fat percentage; the tool derives lean mass and applies an activity multiplier for total daily expenditure.
Background
Published by Cunningham (1980), this approach reflects that metabolically active tissue—not fat—drives most energy expenditure at rest. It can track better than weight-only formulas when body composition is available.
When to use it
Suitable when you have a reliable body-fat estimate (DEXA, calipers, BIA) and want caloric targets that account for muscle mass, common in sports nutrition and recomposition planning.
Limitations
Accuracy depends heavily on body-fat measurement quality—consumer scales and handheld BIA devices can error by several percentage points. The original sample was athletic; very high adiposity or clinical conditions may reduce fit. Not validated for children or pregnancy.
Health disclaimer
Results are estimates for educational planning, not medical nutrition therapy. Seek guidance from a qualified professional before aggressive deficits, refeed protocols, or dietary changes related to health conditions.