How should I split carbs, fat, and protein?
The Acceptable Macronutrient Distribution Ranges (AMDR) are 10–35% of calories from protein, 45–65% from carbohydrates, and 20–35% from fat. For 2,000 kcal/day that is 50–175 g protein, 225–325 g carbs, and 44–78 g fat.
Macro ranges (grams per day)
Protein
Carbohydrate
Fat
How is this calculated?
- Ranges: AMDR from the Institute of Medicine, Dietary Reference Intakes (2005) — protein 10–35%, carbohydrate 45–65%, fat 20–35% of calories.
- Calories to grams: using Atwater general factors of 4 kcal/g for protein, 4 kcal/g for carbohydrate, and 9 kcal/g for fat (the factors used on Nutrition Facts labels).
Example: 2,000 kcal/day
| Macronutrient | AMDR (% of calories) | Grams per day |
|---|---|---|
| Protein | 10–35% | 50–175 g |
| Carbohydrate | 45–65% | 225–325 g |
| Fat | 20–35% | 44–78 g |
The AMDR ranges are wide because there is no single correct split for everyone. They describe the range of intakes that provide adequate essential nutrients while lowering the risk of chronic disease — not a prescription for any one person. Within the ranges, your split can follow your goals and preferences.
Sources
- Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (2005).
- Merrill AL, Watt BK. Energy Value of Foods: Basis and Derivation. USDA Agriculture Handbook No. 74 (1973) — Atwater general factors (4/4/9 kcal per gram).