Medical & Scientific Sources

The references behind the nutrition and fitness figures in the app.

Last updated: 2026-08-14

Basal metabolic rate

Calculated with the Mifflin-St Jeor equation, chosen because it estimates resting energy expenditure more accurately than the older Harris-Benedict equation across most modern populations.

• Mifflin MD, St Jeor ST, et al. (1990)
  A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr 51(2):241-7.

Total daily energy expenditure

Your basal rate is multiplied by an activity factor between 1.2 (sedentary) and 1.9 (very intense daily training), following the standard physical activity level multipliers.

• FAO / WHO / UNU (2004)
  Human energy requirements: report of a joint expert consultation. Section 5.3 covers physical activity levels.

Calories per kilogram of body mass

Weight-change projections use roughly 7,700 kcal per kilogram of body mass.

It is a planning approximation, not a physical constant. The paper below is the reason we say so: the figure fits people carrying more fat and overestimates the deficit needed by leaner ones.

• Hall KD (2008)
  What is the required energy deficit per unit weight loss? Int J Obes (Lond).

Calories in macronutrients

Protein and carbohydrate are counted at 4 kcal per gram and fat at 9 kcal per gram — the Atwater general factors, which are the basis of nutrition labelling worldwide.

• FAO Food and Nutrition Paper 77 (2003)
  Food energy — methods of analysis and conversion factors. Chapter 3 covers energy conversion factors.

Protein targets

Protein options range from 1.6 to 2.2 g per kilogram of body weight, with 1.6 g/kg as the floor the app will not go below when it rebalances your macros.

The position stand below puts 1.4-2.0 g/kg/day as sufficient for most exercising people, and 2.3-3.1 g/kg/day for trained people eating at a deficit. Our range sits inside that span, weighted toward preserving lean mass while losing weight.

• Jäger R, et al. (2017)
  International Society of Sports Nutrition position stand: protein and exercise. J Int Soc Sports Nutr.
• Institute of Medicine (2005)
  Dietary Reference Intakes for energy, carbohydrate, fiber, fat, fatty acids, cholesterol, protein, and amino acids.

Fat targets

Fat is set at 30% of calories while losing weight and 25% otherwise, which keeps intake inside the acceptable macronutrient distribution range and above the level needed for hormone production and absorption of fat-soluble vitamins.

• Institute of Medicine (2005)
  Dietary Reference Intakes — acceptable macronutrient distribution ranges.

Body mass index

BMI categories follow the World Health Organization classification: overweight at 25 and above, obesity at 30 and above.

BMI does not distinguish muscle from fat. It is a population screening tool, not an individual diagnosis.

• World Health Organization
  Obesity and overweight — fact sheet.

Where food nutrition figures come from

Be clear about this one: the app does not query a food composition database. Nutrition figures come from AI analysis and from entries other users have shared, and neither is laboratory-verified.

The database below is the authoritative reference to check a figure against when it matters.

• USDA FoodData Central
  The US Department of Agriculture's food composition and nutrient database.

A note on all of the above

These references describe averages across studied populations. They are the best general starting point available; they are not a measurement of you.