METHODOLOGY

The Formulas

Four equations. Each with a different history, different assumptions, and different ideal use cases.

011990

Mifflin-St Jeor

The modern gold standard

Accuracy

Developed by MD Mifflin and ST St Jeor, this equation was derived from a study of 498 healthy adults. It consistently outperforms older equations in predicting resting metabolic rate and is the formula most recommended by dietitians today.

EQUATION
♂ Male(10 × kg) + (6.25 × cm) − (5 × age) + 5
♀ Female(10 × kg) + (6.25 × cm) − (5 × age) − 161
kgBody weight in kilograms
cmHeight in centimetres
ageAge in years
STRENGTHS
  • +Validated across large, diverse populations
  • +No body fat % measurement required
  • +Most accurate for average body compositions
LIMITATIONS
  • −Less accurate at extremes of body fat
  • −Does not account for lean mass directly
BEST FORMost people — general population

Nutritional Physiology & MPS

Nitrogen Balance & Hypertrophy

Protein intake is the primary driver of Nitrogen Balance. To remain in an anabolic state, nitrogen intake must exceed excretion. The 0.7g/lb baseline is the clinically observed "saturation point" where muscle protein synthesis is fully optimized.

The mTOR Pathway & Leucine

The Mammalian Target of Rapamycin (mTOR) pathway regulates cell growth. Leucine, a branched-chain amino acid, acts as the primary chemical trigger for this process. A high-protein environment ensures a consistent 2.5g+ Leucine spike per feeding cycle.

Thermic Effect of Food (TEF)

Protein requires significant metabolic energy to process. Approximately 20-30%of protein calories are burned during digestion, compared to > 10% for carbohydrates and fats, providing a metabolic advantage for body composition.

Bioavailability Metrics

This formula assumes consumption of high-quality sources with highBiological Value (BV) and PDCAAS scores, such as whey, eggs, or isolated plant proteins, to ensure effective amino acid absorption.