Body recomposition: losing fat while keeping muscle

Body recomposition — losing fat while keeping or gaining lean mass — is the outcome most people want but few achieve. The calorie arithmetic is the same as any deficit, but the approach to protein and the expectation of progress are different.

Why recomposition is harder to see

A straight cut is easy to track: the scale moves down. Recomposition is not. Fat leaves and muscle enters at the same time, so the scale can stay flat — or even rise slightly as glycogen and water shift — while body composition improves. No calculator can detect that, and that is why recomposition is the clearest example of a deliberate limit: this tool tells you how to eat and stops there.

Calorie target

The body recomposition calculatorruns at a gentler deficit than an aggressive cut — a 20% shortfall from your TDEE rather than a 15% cut — because the main risk of getting recomposition wrong is losing lean mass alongside the fat. That makes the protein target critical.

Protein target

At a 20% deficit, the calculator prescribes the higher end of the protein range. The protein calculator recommends 1.6–2.0 g/kg for cutting and building — the range for people who exercise regularly per theISSN Protein Position Stand (2017). (The general RDA for sedentary adults is 0.8 g/kg/day.) The midpoint of that range is the recommended value.

Training, not just diet

Resistance training is what signals your body to hold onto muscle. Cardio burns calories but does not signal muscle retention. A recomposition diet without progressive overload lifting is a cut, not a recomposition.

Track your lifts alongside your weight. If strength is rising while the scale is flat, you are likely recomposing. If both are falling, the deficit is too large.

When to reassess

Recomposition is slow — expect months, not weeks. If after eight weeks the scale is unchanged and measurements are not shifting, either: your body-fat estimate is wrong, your activity level has changed, or the deficit is not real. Recalculate your TDEE at your current weight and check the math.

The body fat calculator and FFMI calculator are the tools to tell, even if the scale cannot.

Formulas are estimates, not medical advice.

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