Body metrics & BMI
From your height and weight we compute BMI (weight ÷ height²) and classify it against WHO categories. Very low or very high readings prompt a gentle nudge to talk to a professional — BMI is a screening signal, not a diagnosis.
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Sources of recommendations
Every calorie target, macro split and nutrition score in Bitsy is built on public-health guidelines and peer-reviewed research. Here's where the numbers come from.
Bitsy is a food tracking app to help you build mindful eating habits. It is not a medical device and does not diagnose, treat or prevent any condition. Bitsy is not affiliated with or endorsed by the organizations cited below.
Calorie targets
Daily calories are estimated with the Mifflin–St Jeor equation for BMR, multiplied by an activity factor (1.2–1.9) for TDEE, then adjusted for your goal. Targets never drop below a sex-aware safety floor — 1,200 kcal for women and 1,500 kcal for men.
Weight loss & gain
You pick a weekly pace between 0.1 and 1.0 kg (default 0.5 kg). We translate it into a daily deficit or surplus using the widely-used ~7,700 kcal-per-kilogram estimate — bounded to safe, sustainable rates, not aggressive crash plans.
Macros
Protein is set as a share of your daily calories that shifts with your goal (20% maintain, 25% gain, 30% loss), with a per-kilogram safety floor — 0.83 g/kg for maintenance and gain, 1.4 g/kg during a deficit to help preserve muscle — and capped at the upper AMDR limit (35% of energy). Fat is held at 25% of calories, with carbs filling the rest.
Hydration
A daily water goal is estimated from your body weight (≈30 ml/kg), with small adjustments for sex and activity, then kept within a sensible 1.5–4 L range — based on EFSA and U.S. reference intakes for total water.
Bitsy nutrition score
Each meal gets a 0–100 score (S–D tiers) estimated by AI from your photo and description, weighed against public-health guidelines. Whole foods, vegetables, fiber and protein lift it; liquid sugar, ultra-processed foods, deep-fried dishes, processed meat and fast food pull it down. It's a quick visual estimate, not a lab analysis.
Food & nutrition data
Calorie and macro values are currently estimated by AI from your meal photos and entries. We're building a curated food-composition database to ground and cross-check these values — that work is in progress.
Carbs & fats
Bitsy favors whole grains and unsaturated fats, and flags added sugar, deep-fried foods and heavy saturated fat.
Fiber, vitamins & minerals
Meals rich in vegetables, fruit, legumes and fiber are read as positive signals of micronutrient quality — guided by national dietary reference intakes. Bitsy estimates these from what it sees, not from lab measurement.