Basal Energy Expenditure (Mifflin–St Jeor & Harris–Benedict)
Estimates resting/basal energy expenditure using the Mifflin–St Jeor equation (preferred) with the classic Harris–Benedict equation for comparison.
Formula
W = weight (kg), H = height (cm), A = age (years). Harris–Benedict (1919): men 66.5 + 13.75W + 5.003H − 6.775A; women 655.1 + 9.563W + 1.850H − 4.676A.
Caveats & limitations
- Predictive equations estimate group-level expenditure; individual variation is substantial.
- In obesity, the choice of actual vs adjusted weight changes results — follow dietetic policy.
- Does not account for illness stress factors; critical care feeding targets are a separate assessment.
Evidence & UK guidance
Primary evidence
Mifflin MD, St Jeor ST, Hill LA, et al. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr. 1990;51(2):241–247.
Harris JA, Benedict FG. A biometric study of human basal metabolism. Washington, DC: Carnegie Institution of Washington; 1919.
UK practice
Mifflin–St Jeor is generally the most accurate predictive equation in non-obese and moderately obese adults and is widely used in UK dietetic practice. All predictive equations carry roughly ±10–20% individual error; use indirect calorimetry when precision matters (e.g. critical care) and clinical judgement for obesity, oedema or amputation.
Formula and citations last verified: 2026-08-03