Key facts
- Protein and carbs provide 4 kcal per gram; fat provides 9.
- Protein builds and repairs muscle; carbs fuel training; fat supports hormones.
- Total calories drive weight; macro split shapes body composition and performance.
- A common protein target is 1.6–2.2 g per kg of bodyweight.
Every calorie you eat comes from one of three macronutrients. Protein and carbohydrates each provide about 4 calories per gram, while fat provides 9. Your total calorie intake determines whether you gain or lose weight; how you split those calories between the three macros influences body composition, performance, and how you feel.
Protein is the macro to prioritize: it builds and repairs muscle and is the most satiating, so it is set first — commonly 1.6–2.2 g per kg of bodyweight. Carbohydrates are the body's preferred training fuel and support recovery. Dietary fat is essential for hormone production and absorbing fat-soluble vitamins, so it shouldn't be cut too low.
Once protein is set, carbs and fat fill the remaining calories according to preference and training demands — athletes doing lots of high-intensity work usually benefit from more carbs. A macro calculator turns your calorie target and goal into gram targets for each.
Frequently asked questions
What are the three macronutrients?
Protein, carbohydrates, and fat. Protein and carbs supply 4 calories per gram and fat supplies 9 calories per gram.
Which macronutrient is most important?
For body composition, protein is usually prioritized because it builds and preserves muscle and is the most filling. Carbs and fat are then balanced around training needs and personal preference.
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