Besly
Sources of recommendations
Besly is a nutrition and fitness tracking app that provides general guidelines and estimates to help you understand your own eating and activity. Besly is not intended for the diagnosis, treatment or prevention of any disease or medical condition, and is not a medical device. Always consult a doctor or a registered dietitian before making health decisions, and especially before starting any restrictive way of eating.
This page lists what each number in the app is based on, and — just as importantly — what it is not. We would rather tell you the limits of an estimate than present it as more precise than it is.
Daily calorie target
Your basal metabolic rate is calculated with the Mifflin-St Jeor equation from your age, sex, height and weight. That figure is multiplied by an activity factor derived from your recent logged activity and steps (a trailing average that excludes the current, incomplete day), then adjusted by the weight goal and pace you chose. Because the factor follows your real activity, your target moves as your habits move rather than staying frozen at a value you picked once.
Limits: every equation of this kind is a population estimate. Individual metabolism varies, and no formula replaces measured energy expenditure.
Mifflin MD et al., A new predictive equation for resting energy expenditure — Am J Clin Nutr, 1990
Macronutrient ranges
Carbohydrate, protein and fat distributions follow the ranges published in the Dietary Guidelines for Americans 2020-2025.
Dietary Guidelines for Americans 2020-2025 — USDA & HHS
Protein target
Protein is set per kilogram of body weight, within the range described by reference intake guidance, with higher values used when you select a muscle-building or high-protein goal.
NIH Office of Dietary Supplements — Nutrient fact sheets
Activity and steps
Movement targets follow the World Health Organization physical activity recommendations for adults.
WHO — Physical activity fact sheet
Sleep and recovery
Sleep duration guidance follows CDC adult sleep recommendations. Heart-rate variability and resting heart rate are never judged against population norms — they are compared only to your own rolling baseline, and read as a trend, not a verdict.
Limits: HRV and resting heart rate are influenced by illness, alcohol, caffeine, stress and measurement conditions. Besly does not interpret them clinically.
Daily score
The daily 0-100 score is a weighted average of individual signal scores: sleep, heart-rate variability, resting heart rate, workouts, steps, calories and protein. The weights are normalised so the total always sums to 1. For display it is grouped into three parts:
- Recovery — sleep 50%, HRV 30%, resting heart rate 20%
- Nutrition — calorie adherence 60%, protein 40%
- Activity — workouts 50%, steps 50%
Limits — please read: when a signal is unavailable (for example, if you do not wear a sleep-tracking device), that signal falls back to a neutral placeholder value instead of being excluded. This keeps the score stable from hour to hour, but it means a score built largely on placeholders is not a measurement of your recovery. The app shows which signals were missing. We are replacing this score with an adherence measure computed only from what you actually logged.
Meal score
Each logged meal receives a deterministic 0-100 score calculated from its macros only:
- Protein share (up to 50 points) — full marks at 30% or more of the meal's calories
- Balance (up to 30 points) — points are deducted when fat exceeds 50% or carbohydrate exceeds 65% of calories
- Portion (up to 20 points) — full marks in a 250-800 kcal band, partial outside it
Items under 100 kcal are not scored at all. Limits: fibre, sugar, sodium and micronutrients are not part of this score, because those values are not yet in our food database. A high score therefore means "macro profile of this meal looks reasonable", not "this meal is healthy".
Food and nutrition data
Nutrition values come from a curated catalogue built from public food composition data (including USDA FoodData Central and Open Food Facts) plus manually verified entries for regional dishes and restaurant items. Curated entries require agreement between at least two sources and internal consistency between calories and macros. Where a food is not in the catalogue, the value is an AI estimate and the app labels it as such — estimates are not presented as verified data.
USDA FoodData Central · Open Food Facts
AI coach
The coach answers questions using your own logged data. It is designed to report and explain what you recorded, not to prescribe: numbers it quotes are read from your entries rather than generated. It does not diagnose conditions, and it declines clinical nutrition questions (for example diabetes or kidney diet planning) with a referral to a professional.
Questions
If you think something on this page is wrong or incomplete, tell us — support@besly.co. We would rather correct it.