All Lean comparisons. Une seule formule qui change tout face aux apps calorie majeures.

Premier constat

Why the calorie calculation is broken everywhere

You download a calorie app. You enter your weight, height, age, gender. The app asks you to check an activity box (sedentary / lightly active / active / very active). And it gives you a daily calorie expenditure, your TDEE. This TDEE becomes your reference to slim down, gain muscle, maintain. The problem is that this TDEE is almost always wrong by 300 to 800 kcal. Not out of malice. Out of scientific laziness.

La cause profonde ? Toutes ces apps utilisent une formule de 1919 (Harris-Benedict) ou sa version repeinte de 1990 (Mifflin-St Jeor) to estimate your basal metabolic rate. These formulas depend only on weight, height, age and gender. Not on bodyfat. Yet fat mass spends very little energy compared to lean body mass. Two men of 80 kg, one at 10 % bodyfat, the other at 30 %, do not have the same metabolism. But MFP, Yazio, Cronometer, Lifesum, FatSecret give them the same value.

Then the activity coefficient multiplies this wrong BMR by an almost random number. Next comes metabolic adaptation, totally ignored. Last comes TEF (digestion), locked at a flat 10 % instead of being calculated on ingested macros. Four cascading approximations. The final TDEE has nothing to do with your reality.

Lean BMROn real bodyfat

Lean started from scratch with another obsession : calculate each component precisely, not approximate it. The BMR is calculated via a proprietary patented model that depends on lean body mass. The lean body mass, itself calculated from bodyfat. The bodyfat, measured every week via a simple photo (AI BodyScan). NEAT comes from real steps (HealthKit / Google Fit), not from a static box. EAT comes from the MET of each sport, weighted by effective time. TEF is calculated based on your macros. Adaptation is adjusted week after week according to your cumulative deficit.

Lean vs the 5 major apps, criterion by criterion

Six critères qui décrivent réellement la précision d’un tracker. Aucun critère ne porte sur le prix.

Criterion

Lean

MyFitness
Pal

Yazio

Cronometer

Lifesum

FatSecret

BMR on real bodyfat

Auto NEAT (steps + non-sport activity)

EAT (calories per session)

−

TEF from macros

−

Metabolic adaptation

Scan IA repas (photo)

−

−

Honest read. Cronometer remains very solid on TEF calculation by macros (heritage of its rigorous micronutrition philosophy) and offers per-session tracking finer than other competitors. But none of the 5 calculates metabolic adaptation, and none bases its BMR on real bodyfat. The AI meal scan remains a general weak point : MFP offers a limited camera mode, FatSecret only offers the barcode.

What Lean does differently

Trois piliers de méthode. Pas de coefficient magique, pas de case statique, pas d’estimation forfaitaire.

Patented BMR

Measured NEAT

Auto adaptation

BMR on lean mass, not your weight

BMR via a patented proprietary model, based on real lean mass derived from bodyfat measured weekly via BodyScan AI. One photo, 5 seconds.

BMR is the first building block of TDEE and the first mistake competitors make. Lean rejects Harris-Benedict, rejects Mifflin-St Jeor, and applies a patented proprietary model based on lean mass as the main variable. To measure this lean mass without a 100 € DEXA scan every week, the app uses BodyScan AI : one photo of you in underwear, a model trained on a DEXA reference bank, your bodyfat estimated in seconds. Repeated every week. BMR readjusts automatically.

NEAT, EAT, TEF: measured, not estimated

NEAT, EAT, TEF calculated separately, from measured data. No activity box to tick.

NEAT. Your real steps, pulled from HealthKit (iOS) or Google Fit (Android), cross-referenced with your BMR. No self-reporting, no rough estimate. EAT. For every workout, you pick the sport (lifting, running, tennis, swimming, etc.) and Lean applies its MET (Metabolic Equivalent Task) over effective time (not total time with breaks, the error every smartwatch makes 100 % of the time). TEF. Protein costs 20 to 30 % in digestion, carbs 5 to 10 %, fat 1 to 3 %. Lean computes your TEF from the exact composition of your macros, not a flat 10 %.

Metabolic adaptation: the brick no one calculates

Automatic metabolic adaptation. First consumer app to do it, to our knowledge. Patented proprietary model.

When you are in a prolonged deficit, your body shifts into energy-saving mode. Your BMR drops, your NEAT drops, your TDEE drops. For a deficit of −500 kcal/day, adaptation reaches 10 to 15 % within 4 to 6 weeks. That is the main reason behind plateaus no one can explain. Lean adjusts your TDEE downward week after week based on your cumulative deficit, without asking. When adaptation reaches 10 to 15 %, the app can suggest a return to maintenance to reset your BMR before going back into a deficit.

See your real TDEE broken down, without an activity coefficient to choose. Free download.

Les 5 alternatives à examiner

Chaque carte ouvre un comparateur 1v1 complet : tableau honnête, scorecard où le concurrent gagne quand il gagne, et liste détaillée des écarts.

Lean vs MyFitnessPal

Le standard historique du calorie counting. Base communautaire massive, Mifflin-St Jeor 1990, coefficient d’activité à 4 cases.

Where Lean wins : BMR on real bodyfat, automatic metabolic adaptation, unlimited AI meal scan vs a noisy database and a weight-only BMR.

Voir le comparatif →

Lean vs Yazio

Polished ergonomics, meal plans, strong European audience. TEF estimated by food category, without a bodyfat model.

Where Lean wins : AI BodyScan, measured NEAT on steps, EAT per sport MET, metabolic adaptation vs a static activity coefficient.

Voir le comparatif →

Lean vs Cronometer

Reference of micronutrients, rigorous NCCDB food database, endorsed by dietitians. Stays on Mifflin-St Jeor 1990 without bodyfat on TDEE.

Where Lean wins : BMR on real bodyfat via AI BodyScan, automatic metabolic adaptation, NEAT on real steps vs an activity coefficient locked at signup.

Voir le comparatif →

Lean vs Lifesum

Scandinavian lifestyle app, pre-built diets (keto, vegan, paleo), daily nutrition score. Simplistic TDEE calculation.

Where Lean wins : scientific precision replaces lifestyle recipes. BMR on bodyfat, 5 TDEE components calculated separately, auto adaptation.

Voir le comparatif →

Lean vs FatSecret

Free basic app, large community catalog, standard barcode scan. No scientific ambition on TDEE.

Where Lean wins : complete scientific method on the 5 TDEE components vs a purely declarative food journal.

Voir le comparatif →

Lean vs Noom

Coaching psychologique, cours quotidiens, classification aliments vert/jaune/rouge, coachs humains. Moteur TDEE sur Mifflin-St Jeor 1990, sans bodyfat ni adaptation.

Où Lean gagne : BMR sur bodyfat réel, adaptation métabolique automatique, NEAT sur pas réels face à un coaching psychologique posé sur un calcul TDEE simpliste.

Voir le comparatif →

Frequently asked questions