All formulas used by Calvor

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 high Biological Value (BV) and PDCAAS scores, such as whey, eggs, or isolated plant proteins, to ensure effective amino acid absorption.

Clinical Literature

  • Phillips et al. (2011): Optimal protein for athletes.
  • Morton et al. (2018): Meta-analysis on 1.6g/kg limits.
  • Schoenfeld (2018): Protein timing and hypertrophy.
  • Helms et al. (2014): Protein needs in energy-restricted resistance-trained athletes.

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 high Biological Value (BV) and PDCAAS scores, such as whey, eggs, or isolated plant proteins, to ensure effective amino acid absorption.

Clinical Literature

  • Phillips et al. (2011): Optimal protein for athletes.
  • Morton et al. (2018): Meta-analysis on 1.6g/kg limits.
  • Schoenfeld (2018): Protein timing and hypertrophy.
  • Helms et al. (2014): Protein needs in energy-restricted resistance-trained athletes.
HYDRATION

Water Intake

4L
3L
2L
1L
0.0
Moderately Active · 40ml/kg

Calculated using biometric water-to-mass ratios adjusted for activity thermogenesis.

03

REFERENCE_GUIDE

< 18.5UNDERWEIGHT

Possible nutrient deficiency or underlying health issues.

18.5 – 25HEALTHY

Ideal balance of weight relative to height. Lower risk of disease.

25.0 – 30OVERWEIGHT

Increased risk for cardiovascular stress and metabolic issues.

≥ 30.0OBESE

Significant risk for type 2 diabetes, hypertension, and heart disease.

THE FORMULA

BMI is calculated as kg/m2. It provides a simple numeric measure of a person's thickness or thinness, allowing health professionals to discuss weight problems more objectively with their patients.

LIMITATIONS

While useful for populations, it does not account for age, sex, bone structure, or fat distribution (visceral vs. subcutaneous), which are all critical markers of metabolic health.

IMPORTANT_ADVISORY: MUSCLE_DENSITY

BMI is a generalized screening tool and does not directly measure body fat percentage. For individuals with high muscle density(athletes, bodybuilders), the scale often fails. Because muscle is roughly 18% denser than fat, highly fit individuals may be categorized as "Overweight" or "Obese" despite having athletic levels of body fat.

OFFICIAL SOURCEWorld Health Organization (WHO) Global DatabaseREF: 2026_METRIC_STANDARD