Body Recomposition Calculator

This calculator evaluates two primary factors — training experience and body fat level — and assigns a score to each. The combined score determines your feasibility rating: HIGH (score ≥4), MODERATE (score ≥2), or LOW (score <2). This approach reflects the research: the two strongest predictors of recomposition success are training novelty and available fat reserves.

Calorie cycling — eating slightly more on training days and slightly less on rest days — is a practical strategy for body recomposition. Training days allocate more carbohydrates to fuel performance and recovery, while rest days shift toward a higher fat percentage with fewer carbs.

This calculator estimates your TDEE using the Cunningham equation (which uses lean body mass for accuracy) multiplied by a moderate activity factor of 1.55. Training day calories are set at TDEE × 1.05 and rest day calories at TDEE × 0.95. Protein is fixed at 2.2 g/kg on both days to maximise muscle protein synthesis.

For advanced, lean athletes, the body's capacity for recomposition diminishes. Muscle protein synthesis rates are lower in trained individuals (the repeated bout effect), and leaner body compositions leave less fat available to mobilise without compromising hormonal function.

At this point, dedicated cut and bulk cycles of 8–16 weeks produce faster results because hormonal and metabolic conditions are optimised for a single goal. A moderate surplus supports maximal muscle gain, while a dedicated deficit preserves muscle while efficiently reducing fat mass.

Successful body recomposition depends on four pillars: high protein intake (2.0–2.4 g/kg body weight), progressive resistance training with an emphasis on compound movements, adequate sleep (7–9 hours per night), and patience.

The rate of change during recomp is slow — often imperceptible on a weekly basis. Tracking body measurements and strength progress is more useful than tracking scale weight, which may remain stable even as body composition improves significantly.

Muscle protein synthesis remains elevated for 24–48 hours after a resistance training session. This means rest days are not recovery-only days — they are active muscle-building days from a physiological perspective. Reducing protein on rest days undermines the very process you are trying to optimise.

This calculator keeps protein at 2.2 g/kg on both training and rest days. The calorie difference between days comes from carbohydrates and fat, not protein. Training days get more carbs (25% fat) to fuel performance, while rest days shift to a higher fat ratio (30% fat) with fewer carbs.