During periods of intentional weight change (cutting or bulking), higher protein intake (1.6-2.2 g/kg/day) helps preserve lean mass during calorie restriction and supports muscle protein synthesis during calorie surplus.

In plain English

Eating more protein, about 1.6 to 2.2 grams per kilo of body weight a day, helps you hold onto muscle while losing fat and build more muscle while gaining. Lower intakes do both jobs less well.

Why it works

Higher protein intake increases muscle protein synthesis rates and reduces muscle protein breakdown, particularly important when energy availability is restricted. The leucine content of dietary protein directly stimulates the mTOR pathway.

The evidence

• Aragon, A.A., Schoenfeld, B.J., Wildman, R. et al. (2017). International Society of Sports Nutrition Position Stand: Diets and Body Composition. Journal of the International Society of Sports Nutrition.

• Helms, E.R., Aragon, A.A., Fitschen, P.J. (2014). Evidence-Based Recommendations for Natural Bodybuilding Contest Preparation: Nutrition and Supplementation. Journal of the International Society of Sports Nutrition.

• Lambert, C.P., Frank, L.L., Evans, W.J. (2004). Macronutrient Considerations for the Sport of Bodybuilding. Sports Medicine.

Why we call confidence high

ISSN position stand (Aragon et al. 2017) and multiple systematic reviews consistently support elevated protein intake for body composition outcomes during energy restriction and surplus.

Where it applies

Healthy adults