What this calculator measures
Body recomposition — gaining muscle while losing fat — is achievable but slower and less obvious on the scale than a dedicated cut or bulk. It is best suited to beginners, returning trainees, or those returning from a break, where the body's sensitivity to both protein and training stimulus is elevated.
How this calculator works
This calculator uses a small 5% calorie deficit from maintenance combined with a high protein target of 2.1 g/kg body weight — the key nutritional conditions for supporting muscle protein synthesis while in a slight energy deficit. The approach is supported by ISSN protein research on body composition during energy restriction.
How to use your result
Measure progress with multiple methods — body fat percentage, waist measurements, strength levels, and photos — rather than scale weight alone. The scale may barely move during effective recomposition as fat mass falls while muscle mass rises. Allow 8–16 weeks for meaningful results. If progress stalls completely, consider a short dedicated cut or bulk phase.
Who recomposition works best for
Three groups see the clearest results: people new to resistance training, people returning after a long break, and people carrying higher body fat. All three have room to add muscle while energy comes from stored fat.
A lean, well-trained lifter has the hardest time. For them, dedicated gaining and cutting phases usually produce more progress per month than trying to do both at once.
How to measure progress when the scale will not move
Recomposition deliberately produces a flat scale. Fat mass falls while lean mass rises, and body weight sits still for weeks. Judging the process by weight alone makes a working plan look like a failed one.
Use four measures instead: waist circumference at a fixed landmark, progress photos in the same light and pose, working-set loads on two or three main lifts, and how clothes fit. If the waist is shrinking while lifts climb, recomposition is happening regardless of the scale.
Important limitation
Calculator results are estimates. Pregnancy, eating disorders, medical conditions, injuries, or concerning symptoms require qualified professional guidance.