Scientific work
Your calorie target is an estimate based on the published research below. It is a starting point, not medical advice. Real needs vary from person to person.
Resting calories
Base calories are calculated with the Mifflin-St Jeor equation from weight, height, age and sex.
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Mifflin MD, St Jeor ST, et al. (1990)
A new predictive equation for resting energy expenditure in healthy individuals. The American Journal of Clinical Nutrition 51(2): 241–247. DOI -
Frankenfield D, Roth-Yousey L, Compher C (2005)
Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review. Journal of the American Dietetic Association 105(5): 775–789. Found the Mifflin-St Jeor equation the most accurate of the common equations. DOI
Activity level
Base calories are multiplied by a physical activity level (PAL): 1.4 for mostly sitting, 1.6 for light movement, 1.8 for active and 2.0 for very active. The values follow the FAO/WHO/UNU ranges. With connected health data, the app adds the day’s active calories instead.
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FAO/WHO/UNU (2004)
Human energy requirements. Report of a Joint FAO/WHO/UNU Expert Consultation. FAO Food and Nutrition Technical Report Series 1. Rome. FAO
Weekly pace
The daily deficit or surplus assumes about 7,700 kcal per kilogram of body weight. This is a simplification: weight change usually slows over time, so the goal date is an illustration, not a prediction. Loss plans never go below 1,500 kcal a day (1,200 kcal for women); these limits are app defaults.