Body recomposition

Body recomposition is losing fat and gaining muscle at the same time, which can happen in a small calorie deficit or surplus.^{1Helms et al., The Muscle & Strength Pyramid: Nutrition, 2nd ed., p. 66.} It depends on the client’s training status, program and nutrition: untrained clients can lose fat and gain lean mass with calorie restriction and training, but trained clients who are already lean have a harder time.^{2Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 131.} Muscle growth in a deficit is possible, though smaller than in a surplus.^{3Schoenfeld, Science and Development of Muscle Hypertrophy, 2nd ed., p. 221.}

Body weight can hide the change in body composition.^{4Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 534.} Muscle holds far fewer calories per pound than fat, so weight can even rise in a deficit.^{5Helms et al., The Muscle & Strength Pyramid: Nutrition, 2nd ed., p. 63.},^{6Helms et al., The Muscle & Strength Pyramid: Nutrition, 2nd ed., p. 64.} In one 16-week study, overweight older men new to resistance training lost 1.1 kg of fat and gained 1.7 kg of muscle while in a deficit of about 65 kcal a day.^{5Helms et al., The Muscle & Strength Pyramid: Nutrition, 2nd ed., p. 63.},^{6Helms et al., The Muscle & Strength Pyramid: Nutrition, 2nd ed., p. 64.}

In practice

• Beginners and clients returning after time off are the best candidates.^{7Helms et al., The Muscle & Strength Pyramid: Nutrition, 2nd ed., p. 41.} A new lifter can add 5 to 10% to body weight over a year with no rise in body fat percentage.^{7Helms et al., The Muscle & Strength Pyramid: Nutrition, 2nd ed., p. 41.}
• Expect slow changes, especially in well-trained clients.^{1Helms et al., The Muscle & Strength Pyramid: Nutrition, 2nd ed., p. 66.} Helms recommends separate fat loss and muscle gain phases once a lifter is past the novice stage.^{1Helms et al., The Muscle & Strength Pyramid: Nutrition, 2nd ed., p. 66.},^{7Helms et al., The Muscle & Strength Pyramid: Nutrition, 2nd ed., p. 41.}
• Track fat mass and fat-free mass if possible, rather than relying on weight alone.^{4Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 534.}