MacronutrientMacros

Macronutrients — protein, carbohydrate and fat — are the nutrients the body needs in large amounts and which supply energy (calories). Alcohol also provides calories but isn't an essential nutrient.

They matter because their balance shapes body composition and performance: protein supports muscle, carbohydrate fuels hard training, and fat supports hormones and health. Total calories set weight change, but the macro split influences how you feel, perform and partition that weight.

In practice, people set a protein target first, then divide the remaining calories between carbohydrate and fat to suit their training and preferences.