Energy expenditure
BMR is estimated with Mifflin-St Jeor (default), the Roza & Shizgal revision of Harris-Benedict, and — when body fat is known — Katch-McArdle and Cunningham. TDEE = BMR × activity factor (1.2, 1.375, 1.55, 1.725, 1.9).
Goals and weight projection
Goal presets scale maintenance calories by a percentage (−25% to +15%). The cutting planner simulates weight day by day: each day's TDEE is recomputed from the current weight, and the energy gap is converted to body-mass change at 7,700 kcal/kg. This is a simplification — real change also involves water, glycogen and adaptive thermogenesis — so projections are estimates.
Macronutrients
Protein ranges follow the ISSN position stand (1.4–2.0 g/kg), the Morton et al. 2018 meta-analysis (plateau ≈1.6 g/kg, upper CI ≈2.2 g/kg) and Helms et al. 2014 for lean individuals in a deficit (up to 2.3–3.1 g/kg of lean mass). Fat defaults sit inside the 20–35% Acceptable Macronutrient Distribution Range.
Body composition
- U.S. Navy circumference method (Hodgdon & Beckett), metric form.
- Jackson-Pollock 3-site skinfolds with the Siri equation (BF% = 495/density − 450).
- Relative Fat Mass (Woolcott & Bergman 2018): 64 − 20·height/waist (+12 for women).
- Deurenberg BMI-based estimate (1991).
- FFMI (Kouri et al. 1995): lean mass / height², normalised = FFMI + 6.1 × (1.8 − height m).
Ideal weight
Devine (1974), Robinson (1983), Miller (1983) and Hamwi (1964), each a base weight at 5 ft plus a fixed increment per inch, compared with the BMI 18.5–24.9 range.
Hydration
Baseline from EFSA adequate intakes for total water (2.0 L women, 2.5 L men, ~80% from drinks), plus estimated sweat losses during exercise and adjustments for heat, altitude, pregnancy and lactation.
Strength
One-rep max from Epley, Brzycki, Lombardi, O'Conner, Lander, Mayhew and Wathan; most accurate with sets of 10 reps or fewer.
Calories burned
kcal = MET × body mass (kg) × hours, with MET values from the 2011 Compendium of Physical Activities.
Meal planner
For each meal the planner draws a protein, carbohydrate and fat source plus a vegetable or fruit from the food database, filtered by your diet. Portions for the whole day are solved together by bounded coordinate descent, minimising squared relative error on protein (weighted highest), carbs and fat, with a soft constraint keeping each meal near its calorie share. Fourteen candidate days are generated and the closest one is shown. Portions are then rounded to practical amounts.
Food data
Per-100 g values are approximate and compiled from public USDA FoodData Central records (SR Legacy / Foundation Foods); protein powders and similar items use typical label values. Values vary with brand, variety and preparation.
Translations
Pages in Spanish, French, German, Romanian, Hindi and Simplified Chinese are translations of the English originals. Formulas, numbers and cited studies are identical in every language.
See the full list of references on our sources page.