Methodology

A detailed look at the peer-reviewed formulas, data sources, and validation methods behind every Calorique calculator.

Basal Metabolic Rate (BMR)

Calorique implements three peer-reviewed BMR equations, with the Mifflin-St Jeor as the default recommendation. The Mifflin-St Jeor equation was validated in a 2005 systematic review by the American Dietetic Association as the most accurate predictive equation for estimating BMR in non-obese and obese individuals.

Mifflin-St Jeor (1990)

Males: BMR = (10 × weight_kg) + (6.25 × height_cm) - (5 × age) + 5

Females: BMR = (10 × weight_kg) + (6.25 × height_cm) - (5 × age) - 161

Source: Mifflin MD, St Jeor ST, et al. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr. 1990;51(2):241-247.

Harris-Benedict (Revised, 1984)

Males: BMR = (13.397 × weight_kg) + (4.799 × height_cm) - (5.677 × age) + 88.362

Females: BMR = (9.247 × weight_kg) + (3.098 × height_cm) - (4.330 × age) + 447.593

Source: Roza AM, Shizgal HM. The Harris Benedict equation reevaluated. Am J Clin Nutr. 1984;40(1):168-182.

Katch-McArdle (1983)

BMR = 370 + (21.6 × lean_body_mass_kg)

Requires known body fat percentage. Most accurate for athletes and lean individuals. Source: Katch F, McArdle W. Introduction to Nutrition, Exercise, and Health. 1983.

Total Daily Energy Expenditure (TDEE)

TDEE is calculated by multiplying BMR by an activity factor. We use the standard activity multipliers from the National Academy of Sciences Dietary Reference Intakes (2005):

Activity Level	Multiplier	Description
Sedentary	1.2	Little or no exercise, desk job
Lightly Active	1.375	Light exercise 1-3 days/week
Moderately Active	1.55	Moderate exercise 3-5 days/week
Very Active	1.725	Hard exercise 6-7 days/week
Extra Active	1.9	Very hard exercise, physical job, training twice/day

Source: Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. National Academies Press, 2005.

Body Mass Index (BMI)

BMI is calculated using the standard WHO formula: BMI = weight_kg / (height_m)². Classification thresholds follow WHO guidelines:

BMI Range	Classification
< 18.5	Underweight
18.5 - 24.9	Normal weight
25.0 - 29.9	Overweight
≥ 30.0	Obese

We include clear disclaimers that BMI is a screening tool, not a diagnostic measure. It does not account for muscle mass, bone density, age, sex, or ethnicity — all factors that affect its accuracy at the individual level.

Macronutrient Ratios

Our Macro Calculator uses evidence-based ratios from the Acceptable Macronutrient Distribution Ranges (AMDR) established by the National Academy of Medicine. Default distributions are adjusted based on the user's goal:

Maintenance: 30% protein / 40% carbs / 30% fat
Weight loss: 35% protein / 35% carbs / 30% fat (higher protein for satiety and muscle preservation)
Muscle gain: 30% protein / 45% carbs / 25% fat (higher carbs for training fuel)

AMDR ranges: Protein 10-35%, Carbohydrate 45-65%, Fat 20-35% of total calories. Source: IOM Dietary Reference Intakes, 2005.

Body Fat Estimation

Our Body Fat Calculator uses the U.S. Navy circumference method, which has been validated against hydrostatic weighing and DEXA scans:

Males: BF% = 495 / (1.0324 - 0.19077 × log10(waist - neck) + 0.15456 × log10(height)) - 450

Females: BF% = 495 / (1.29579 - 0.35004 × log10(waist + hip - neck) + 0.22100 × log10(height)) - 450

Source: Hodgdon JA, Beckett MB. Prediction of percent body fat for U.S. Navy personnel from body circumferences and height. Naval Health Research Center, 1984.

Calories Burned (MET Method)

Our Calories Burned Calculator uses Metabolic Equivalent of Task (MET) values from the Ainsworth Compendium:

Calories = MET × weight_kg × duration_hours

Source: Ainsworth BE, et al. 2011 Compendium of Physical Activities: a second update. Med Sci Sports Exerc. 2011;43(8):1575-1581.

We cover 50+ activities with verified MET values. Each activity page links to the specific Compendium entry and explains what the MET value represents in practical terms.

Protein Requirements

Our Protein Calculator implements the ISSN (International Society of Sports Nutrition) position stand guidelines:

Sedentary adults: 0.8 g/kg/day (RDA minimum)
Recreational exercisers: 1.0-1.4 g/kg/day
Endurance athletes: 1.2-1.6 g/kg/day
Strength/power athletes: 1.6-2.2 g/kg/day
During caloric deficit: Up to 2.3-3.1 g/kg of lean body mass

Source: Jäger R, et al. International Society of Sports Nutrition position stand: protein and exercise. J Int Soc Sports Nutr. 2017;14:20.

Weight Loss Projection

Our Weight Loss Timeline uses the widely accepted energy balance model:

1 lb of body fat ≈ 3,500 calories

500 cal/day deficit ≈ 1 lb/week loss

Source: Hall KD, et al. Quantification of the effect of energy imbalance on bodyweight. Lancet. 2011;378(9793):826-837.

We include adaptive thermogenesis adjustments — as weight decreases, BMR decreases, so the projected timeline accounts for metabolic adaptation rather than assuming a constant rate.

Validation & Testing

Every calculator is validated against published reference values before deployment. Our testing process includes:

Comparison against example calculations from source papers
Cross-validation with NIH Body Weight Planner, Mayo Clinic, and USDA tools
Edge case testing (extremely high/low values, unit boundary conditions)
Unit conversion accuracy (lbs/kg, in/cm, ft/m)
Browser compatibility testing across Chrome, Firefox, Safari, Edge

Known Limitations

We are transparent about what our calculators cannot do:

Individual variation: All formulas are population-based estimates. Individual metabolism can vary by ±15-20% from predicted values.
Medical conditions: Thyroid disorders, PCOS, diabetes, and medications can significantly affect metabolism. Our calculators do not account for these.
Age extremes: BMR equations are less accurate for children under 18 and adults over 80.
Athletic populations: Highly muscular individuals may get inaccurate BMI readings. We recommend the Katch-McArdle formula and body fat-based calculations for athletes.
Ethnicity: Some BMI thresholds may not apply equally across ethnic groups. The WHO has proposed adjusted thresholds for Asian populations (overweight at BMI 23, obese at BMI 27.5).

References

Mifflin MD, et al. A new predictive equation for resting energy expenditure. Am J Clin Nutr. 1990;51(2):241-247.
Roza AM, Shizgal HM. The Harris Benedict equation reevaluated. Am J Clin Nutr. 1984;40(1):168-182.
Ainsworth BE, et al. 2011 Compendium of Physical Activities. Med Sci Sports Exerc. 2011;43(8):1575-1581.
Jäger R, et al. ISSN position stand: protein and exercise. J Int Soc Sports Nutr. 2017;14:20.
Hall KD, et al. Quantification of the effect of energy imbalance on bodyweight. Lancet. 2011;378:826-837.
Hodgdon JA, Beckett MB. Prediction of percent body fat. Naval Health Research Center. 1984.
Institute of Medicine. Dietary Reference Intakes. National Academies Press, 2005.
WHO. Physical status: the use and interpretation of anthropometry. WHO Technical Report Series 854. 1995.

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