Nutrition glossary
What Are Macros?
**Macros (macronutrients)** are the three nutrients that supply energy: protein and carbohydrates at 4 calories per gram, and fat at 9. While calories decide weight change, your macro split shapes whether that change is muscle or fat.
Tracking macros, not just calories, is how you steer body composition and how good you feel along the way.
Short answer
Macros (macronutrients) are the three nutrients that supply energy: protein and carbohydrates at 4 calories per gram, and fat at 9. While calories decide weight change, your macro split shapes whether that change is muscle or fat.
How it works
Every food you eat breaks down into these macros, and each carries a fixed amount of energy per gram. (Alcohol is a fourth source at 7 calories per gram, though it isn't an essential nutrient.)
- Protein — 4 calories per gram — builds and protects muscle, the most filling macro
- Carbohydrates — 4 calories per gram — your body's main fuel for training and brain function
- Fat — 9 calories per gram — supports hormones and helps absorb vitamins
Why it matters for your goals
Two people can eat the same calories and get very different results depending on their macros. Keep protein high and you protect muscle in a deficit and build it in a surplus; let it fall and you risk losing the tissue you're training for.
A common starting point is to set protein first (around 1.6–2.2g per kg of bodyweight), set fat for hormones and satiety, then let carbs fill the rest of your maintenance calories or goal target. Protein is the macro worth getting right — the rest can flex around your life.
Frequently asked questions
How many calories are in each macro?
Protein and carbohydrates each provide 4 calories per gram, and fat provides 9. Alcohol provides 7 calories per gram but isn't counted as a true macronutrient.
Which macro is most important?
Protein, for most people with a body-composition goal. It preserves muscle, keeps you full, and has the highest thermic effect. Hit your protein target and carbs and fat have far more room to flex.
Do I have to count macros to lose weight?
No — calories drive weight change on their own. But tracking macros, especially protein, makes a big difference to how much muscle you keep and how satisfied you feel while dieting.
Keep exploring
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