How it's calculated
Protein (g per day) = body weight (kg) × grams per kg
| Who | Grams per kg a day | Source |
|---|---|---|
| Adults (RDA) | 0.8 | National Academies DRI |
| Athletes and active adults | 1.2–2.0 | ACSM, Academy of Nutrition and Dietetics, Dietitians of Canada (2016) |
| Most exercising people | 1.4–2.0 | ISSN position stand (2017) |
| Older adults | 1.0–1.2 | PROT-AGE study group (2013) |
To convert pounds to kilograms, multiply by 0.45359237. Per pound, the RDA is about 0.36 g.
Worked example
A person who weighs 180 lb (81.6 kg):
RDA: 81.6 × 0.8 = 65 g a day
Active range: 81.6 × 1.2 = 98 g to 81.6 × 2.0 = 163 g a day
Active range: 81.6 × 1.2 = 98 g to 81.6 × 2.0 = 163 g a day
What the RDA means
The RDA is the amount that meets the needs of nearly all healthy adults. It's a minimum to avoid shortfall, not a ceiling or an optimal target for active people. The ISSN also suggests spreading protein across meals, about 0.25 g/kg (often 20–40 g) per meal.
Limitations
- For people with a high body fat percentage, using total weight can overestimate needs. A dietitian may base it on a reference or adjusted weight.
- People with kidney disease often need a specific limit. Check with a doctor before raising protein.
- Pregnancy and breastfeeding raise protein needs. Follow your care provider's advice.
- Values are for adults. Children and teens have different DRIs.
For anyone under 18, these calculators show a pointer to the CDC's BMI-for-age calculator and growth charts instead of adult results, because children and teens are still growing.
Sources
- Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (2005)
- Thomas DT, Erdman KA, Burke LM. Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and Athletic Performance. J Acad Nutr Diet 2016;116:501–528.
- Jäger R, et al. International Society of Sports Nutrition Position Stand: protein and exercise. J Int Soc Sports Nutr 2017;14:20.
- Bauer J, et al. Evidence-based recommendations for optimal dietary protein intake in older people: a position paper from the PROT-AGE Study Group. J Am Med Dir Assoc 2013;14:542–559.