What is body recomposition?
Body recomposition is the process of simultaneously reducing body fat and increasing muscle mass. Because muscle and fat change in opposite directions, your body weight may barely move even as your waist shrinks and your physique becomes more defined — which is exactly why scale weight alone is a poor measure of recomp progress.
Unlike a traditional 'bulk' (eating in a surplus to gain) or 'cut' (eating in a deficit to lose), recomposition aims to do both at once by eating close to maintenance calories, prioritising protein and training hard. It's slower than dedicated bulking or cutting, but it keeps you lean and muscular year-round.
How this calculator works
First it estimates your Basal Metabolic Rate (BMR) — the calories your body burns at rest — using the Mifflin–St Jeor equation, the most accurate of the common formulas. It then multiplies your BMR by an activity factor to get your Total Daily Energy Expenditure (TDEE), or maintenance calories.
For recomposition, your calorie target is set at maintenance. Protein is set high at 2.0 g per kg of body weight to drive muscle growth and preserve lean mass, fat at 0.9 g per kg to support hormones, and the remaining calories are filled with carbohydrate to fuel training.
Worked example: an 80 kg, 180 cm, 30-year-old man who trains moderately has a BMR around 1,780 kcal and a TDEE near 2,750 kcal. His recomp target is ~2,750 kcal, with roughly 160 g protein, 72 g fat and 340 g carbs.
Recomposition macro split
The macro targets below are the foundation of an effective recomposition. Protein is the non-negotiable: it's what makes building muscle in a non-surplus possible.
| Macronutrient | Target | Why it matters |
|---|---|---|
| Protein | 2.0 g per kg body weight | Builds and preserves muscle near maintenance calories |
| Fat | 0.9 g per kg body weight | Supports hormones and overall health |
| Carbohydrate | Remaining calories | Fuels hard training and recovery |
Who gets the best recomposition results?
Recomposition works fastest for people with the most 'newbie' adaptation potential. You'll see the strongest results if you are new to resistance training, returning after a long break, or carrying a higher body fat percentage — all situations where your body readily builds muscle while drawing on fat stores for energy.
Advanced lifters who are already lean tend to recomp more slowly and often make faster progress with dedicated bulk and cut phases. But for the majority of everyday gym-goers, eating at maintenance with high protein is a sustainable, effective long-term strategy.
Calorie cycling for faster recomposition
A popular refinement is to cycle calories around your training rather than eating the same amount every day. You eat slightly more on training days to fuel muscle growth, and slightly less on rest days to encourage fat loss, while still averaging maintenance across the week.
| Day type | Calories vs maintenance | Emphasis |
|---|---|---|
| Training day | +10% (slight surplus) | Muscle growth and performance |
| Rest day | −10% (slight deficit) | Fat loss and recovery |
| Weekly average | ≈ maintenance | Net recomposition |
Training and protein matter most
No calorie target will recomposition your body without a progressive resistance-training stimulus. Lifting weights 3–5 times per week with a focus on gradually increasing load or reps is the signal that tells your body to build muscle rather than just lose weight. Pair that with hitting your protein target every day and adequate sleep, and recomposition becomes a matter of consistency over months.
How long does body recomposition take?
Recomposition is a marathon, not a sprint. Visible changes usually take 8–12 weeks, with meaningful transformation over 6–12 months of consistent training and nutrition. Because the scale moves little, the best way to track progress is with body measurements, progress photos and strength gains in the gym rather than weight alone.