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Body recomposition explained

What body recomposition is, what a randomised trial found, how much protein and training the research supports, and how to track it with an InBody scan. UnReal Gym Bangkok.

By the UnReal Gym Bangkok team. Updated 2026-10-06.

Short answer

Sometimes, with limits. In a 4 week trial of 40 young men on a large calorie deficit and heavy training, the group eating 2.4 g of protein per kg gained about 1.2 kg of lean mass while losing about 4.8 kg of fat. That was a hard trial, not a template. Training and protein are the common ingredients.

What is body recomposition?

Body recomposition means changing what your weight is made of: less fat, the same or more muscle. The scale may barely move, which is why it is easy to miss without a body composition scan. A scan shows skeletal muscle mass and body fat mass separately, as covered in our InBody result sheet guide.

Can you lose fat and build muscle at the same time?

The evidence says yes in some conditions, and we would not oversell it. Longland and colleagues (2016) ran a randomised trial in 40 young men, 20 per group. For 4 weeks both groups ate about 40 percent below their energy needs and did resistance training plus high intensity interval training 6 days a week. One group ate 1.2 g of protein per kg of bodyweight per day, the other 2.4 g.

The higher protein group gained 1.2 kg of lean body mass and lost 4.8 kg of fat mass. The lower protein group gained 0.1 kg of lean mass and lost 3.5 kg of fat. Body composition was measured with a four compartment model.

Read the limits as clearly as the result. It was 4 weeks, young men, a very high training volume and a large deficit. It shows that protein and training can shift the balance, not that everyone will gain muscle while dieting at that pace.

The International Society of Sports Nutrition (ISSN) adds that slower rates of weight loss can better preserve lean mass in leaner people, so a lean person has less room to push a deficit.

How much protein do you need for body recomposition?

The ISSN protein position stand says 1.4 to 2.0 grams per kilogram of bodyweight per day is sufficient for most exercising people to build and maintain muscle. It adds that higher intakes, 2.3 to 3.1 g per kg, may be needed to maximise the retention of lean mass in resistance trained people during periods of calorie restriction.

Our shop guide to how much protein per day turns that into grams for your weight. If you are asking whether more protein is safe, see is whey protein safe, which reads the kidney evidence.

How should you train for recomposition?

The American College of Sports Medicine position stand on resistance training for healthy adults recommends, for novices, a frequency of 2 to 3 days a week with loads around 8 to 12 repetition maximum. For intermediate lifters it recommends 3 to 4 days a week and for advanced lifters 4 to 5, with load increased by 2 to 10 percent once the current load becomes easy.

If you are starting out, our beginner weight training programme is built on that statement.

How big should the calorie gap be?

The ISSN diets and body composition position stand says fat loss is driven by a sustained calorie deficit, that a higher starting body fat allows a more aggressive deficit, and that slower loss can better preserve lean mass in leaner people. It does not give one number for everyone, and neither will we. A coach can set yours in nutrition coaching.

How do you know it is working?

Do not rely on the scale. Track these over weeks, scanning under the same conditions each time:

  • Skeletal muscle mass holding or rising.
  • Body fat mass falling in kilograms.
  • Your waist measurement and your lifts.

Remember the noise floor. In the McLester study (2020) the smallest body fat percentage change between two InBody scans that beat measurement error was 2.12 to 2.73 points, so give a block of training several weeks before you judge it. See how often to measure body composition and what a good InBody score is.

Who should check with a doctor first?

Anyone with a medical condition, anyone on medication that affects weight or appetite, and anyone with a history of disordered eating should speak to a doctor or dietitian before changing how they eat or train. This page is general information, not advice for your case.

Sources

Updated 2026-10-06