The Acceptable Macronutrient Distribution Range is part of the Dietary Reference Intakes used in the United States and Canada. It was proposed in the Institute of Medicine's 2002/2005 report on macronutrients to give health professionals a range of intakes for the energy-containing macronutrients that is associated with both adequate micronutrient intake and decreased risk of chronic disease. AMDRs are expressed as a percentage of total calories rather than in grams, so the gram amounts scale with each person's calorie needs. Intakes above a range were thought to raise chronic disease risk, and intakes below it to raise the risk of nutrient insufficiency.
The ranges
Percent of total energy, as listed in the National Academies' 2024 review:
| Macronutrient | Ages 1–3 | Ages 4–18 | Adults |
|---|---|---|---|
| Carbohydrate | 45–65% | 45–65% | 45–65% |
| Fat | 30–40% | 25–35% | 20–35% |
| Protein | 5–20% | 10–30% | 10–35% |
Formula
grams = (calories × percentage) ÷ kcal per gram
- calories: daily energy intake, often an estimate of total daily energy expenditure.
- percentage: the chosen share within the AMDR, as a decimal.
- kcal per gram: the general Atwater factors of 4 for carbohydrate, 4 for protein and 9 for fat.
Example
For an adult eating 2,000 kcal a day:
- Carbohydrate: 45–65% = 900–1,300 kcal ÷ 4 = 225–325 g
- Fat: 20–35% = 400–700 kcal ÷ 9 ≈ 44–78 g
- Protein: 10–35% = 200–700 kcal ÷ 4 = 50–175 g
The macro calculator converts a calorie target into grams within these ranges, the protein calculator focuses on protein, and the BMR calculator supplies the basal metabolic rate that the calorie target starts from. The guide to calculating macros works through a full example.
Common mistakes
- Treating the ranges as targets to hit exactly. They are broad bands, and the three chosen percentages must add up to 100%.
- Applying adult ranges to children, whose fat and protein ranges differ.