Macronutrients

Macronutrients, often called macros, are nutrients the diet has to supply in significant amounts: protein, carbohydrate and fat.^{1Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 197.} Carbohydrate and protein each provide 4 kcal per gram, and fat provides 9 kcal per gram.^{2International Personal Trainer Academy, Certified Personal Trainer Textbook, p. 486.} Alcohol isn’t a nutrient, but it still supplies 7 kcal per gram.^{2International Personal Trainer Academy, Certified Personal Trainer Textbook, p. 486.}

Protein mostly builds and repairs tissue, though some is burned for energy, and more is burned when calories or glycogen stores run low.^{3Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 125.} Carbohydrate is the main fuel for sport.^{4Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 124.} The body’s need for fat is small, but diets under about 15% fat may lower testosterone, and very-low-fat diets can impair absorption of the fat-soluble vitamins.^{5Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 126.}

In practice

• Athletes generally need 1.4 to 2.0 g/kg of protein a day.^{3Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 125.} About 1.6 g/kg optimizes strength and muscle gains for most people, and up to 2.2 g/kg may suit clients trying to maximize them.^{3Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 125.}
• Endurance athletes who train 90 minutes or more a day need roughly 7 to 10 g/kg of carbohydrate daily, while 5 to 6 g/kg is reasonable for strength, sprint and skill training.^{5Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 126.}
• With calories and protein set, Helms and colleagues suggest 20 to 30% of calories from fat and the rest from carbohydrate in a calorie surplus.^{6Helms et al., The Muscle & Strength Pyramid: Nutrition, 2nd ed., p. 86.} Outside a diet, they find the fat-to-carbohydrate split makes little difference.^{6Helms et al., The Muscle & Strength Pyramid: Nutrition, 2nd ed., p. 86.}
• Keep clients focused on the quality and quantity of the whole diet, rather than any single food or nutrient.^{7Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 127.}