Body Recomposition: How to Lose Fat and Build Muscle

Use the body recomp calculator to get your calorie and protein targets. This guide explains the strategy behind them.

What is body recomposition?

Body recomposition (“recomp”) is changing your body’s makeup by losing fat and gaining lean mass over the same period. Weight might not move much, but waist size falls and strength rises. It contrasts with the usual cycle of a calorie surplus to build muscle and a deficit to lose fat (Barakat et al., 2020).

Who can recomp?

Review evidence suggests recomposition is easiest for people new to lifting, returning after a layoff, or carrying more body fat, but it has also been documented in trained lifters (Barakat et al., 2020).

Trained lifters can recomp too, particularly with high protein and well-structured training, but gains are slower and there is less margin for error. If you are already lean and experienced, a dedicated gaining phase will build muscle faster.

How many calories do you need to recomp?

Eat between maintenance and about 10% below TDEE. Our calculator uses a 5% deficit for leaner or trained people and 10% when body fat is higher.

Both TDEEs use moderate activity (×1.55). A larger deficit costs you muscle-building capacity and recovery without making recomp faster. If you are unsure of your TDEE, see what TDEE is or use the TDEE calculator.

How much protein do you need to recomp?

Protein supports muscle gain and retention. A meta-analysis of resistance-training trials found that extra protein increased gains up to about 1.6 g per kg a day, with the upper confidence bound near 2.2 g/kg (Morton et al., 2018). The ISSN position stand recommends 1.4–2.0 g/kg for active people and notes higher intakes may help in a deficit (Jäger et al., 2017; Helms et al., 2014).

For recomp we use 2.0 g/kg as a middle point, with 0.8 g/kg of fat and the rest from carbohydrate:

At the 10% deficit, carbs fall to 219 g (woman) and 310 g (man); protein and fat stay the same. For gram targets across body weights, see how much protein you need.

How should you train for recomposition?

• Lift 3–4 times a week, hitting each major muscle group about twice a week.
• Progress over time. Add weight, reps or sets gradually; this is the signal that makes muscle grow.
• Keep some walking. Daily steps raise energy use without adding recovery cost.
• Sleep 7+ hours where possible, because recovery sets how much training you can absorb.

Treat these as practical defaults rather than a prescription; best training varies by experience and goals.

Why does recomposition work at all?

Two things are happening at once. Resistance training tells your body to keep and build muscle, and a modest energy shortfall lets stored fat cover part of the fuel. Protein supplies the building material (Morton et al., 2018). When the training signal is new, your body is more willing to build muscle, which is why beginners and returning lifters respond best.

As training experience grows, that window narrows. Past the beginner stage, recomposition becomes a matter of small gains over months, and many experienced lifters choose to separate phases of building and losing fat instead. Neither approach is wrong; the choice is about patience and goals.

A sample week

For the woman in the tables above (2,127 kcal, 150 g protein), a simple structure looks like this:

The body recomp calculator can set slightly higher calories on training days and lower on rest days while keeping the weekly average close to your target.

How do you track progress when the scale doesn’t move?

Fat and muscle changes can cancel on the scale. Use several measures:

1. Waist circumference at the navel, every two weeks.
2. Strength numbers on the main lifts, weekly.
3. Photos in the same light and pose, every 4 weeks.
4. Body-fat estimate with the circumference method (Hodgdon & Beckett, 1984), using the body fat calculator; it is rough, so watch the trend.
5. Weekly average weight as a sanity check.

Waist falling with strength rising and stable weight is the classic recomp signature.

How long does recomposition take?

Many people notice changes in strength within weeks and in the mirror after a couple of months; large changes take months to years, and slow down the more trained you are. If after 6–8 weeks your waist, weight and lifts are all flat, adjust: reduce calories by 100–150, or if training is stalling, add a few calories. Slow, steady and measured wins in recomposition.