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Macros (macronutrients)

Macros (macronutrients) are the three calorie-providing nutrient classes: protein (4 cal/g), carbohydrates (4 cal/g), fat (9 cal/g). Tracking macro split — not just total calories — improves body-composition outcomes.

Updated May 2026 · 4 min read
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Definition

Macros (macronutrients) are the three calorie-providing nutrient classes: protein (4 cal/g), carbohydrates (4 cal/g), fat (9 cal/g). Tracking macro split — not just total calories — improves body-composition outcomes.

What it means

Typical macro splits: weight loss / cutting (40% protein / 30-40% carb / 20-30% fat), maintenance (30/40/30), bulking (30/45/25). Athletes vary: endurance favors more carb (50-60%); strength athletes more protein (35-40%). Protein target is most-validated: 0.6-0.8g per lb body weight for most lifters, 0.8-1.0g for serious cutters / older adults. Fat minimum: 20% of calories for hormonal health.

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Why it matters

Same calorie deficit, different macro split = different body-composition outcomes. Sufficient protein + lifting → preserve muscle in deficit. Inadequate protein → lose muscle, regain weight as fat after diet ends. Tracking macros is more work than calorie tracking but produces meaningfully better physique outcomes for most people.

Related free tools

Free toolMacro CalculatorGet your daily protein, carb, and fat targets based on calories and goals. Free, no sign-up.Open tool →Free toolCalorie CalculatorEstimate your daily calorie needs based on age, activity, and goals (lose, maintain, or gain). Free and private.Open tool →

Frequently asked questions

How to track?

MacroFactor, MyFitnessPal, Cronometer. Use a kitchen scale; estimating produces 20-30% undercounts.

Carbs evil?

No. They're the preferred fuel for high-intensity training + brain. Low-carb works for some people for fat loss; medium-carb (40-50%) is the sustainable sweet spot for most.

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