Quick answer: The adult RDA is 0.8 g of protein per kg of body weight, so a 70 kg adult needs about 70 × 0.8 = 56 g a day; for regular strength training the published range is 1.6–2.2 g/kg, or 112–154 g.
How it's calculated
Protein per day = body weight (kg) × grams per kg. The RDA of 0.8 g/kg covers the needs of nearly all healthy adults who do little exercise; in the second half of pregnancy it rises to 1.1 g/kg. Some calculators quote 0.83 g/kg instead, the WHO/FAO safe level, which differs by about 4%.
Higher ranges come from expert groups: 1.0–1.2 g/kg for adults over 65 to help keep muscle (PROT-AGE), 1.2–2.0 g/kg for athletes (ACSM, Academy of Nutrition and Dietetics and Dietitians of Canada), and about 1.6 g/kg, up to 2.2, for gains from strength training (Morton 2018 meta-analysis).
These are based on body weight, so for people with a lot of body fat they overstate the need; using a healthy weight for your height gives a fairer figure. The number cannot account for kidney disease or other conditions in which a doctor may set a different amount. To fit protein into a full day's eating, use the macro calculator.
Worked examples
- 70 kg, RDA: 70 × 0.8 = 56 g/day
- 70 kg, strength training: 70 × 1.6 … 2.2 = 112 – 154 g/day
- 80 kg, older adult: 80 × 1.0 … 1.2 = 80 – 96 g/day
Protein in common foods
Approximate protein per typical portion.
| Food | Portion | Protein |
|---|---|---|
| Chicken breast, cooked | 100 g | 31 g |
| Eggs | 2 large | 12 g |
| Lentils, cooked | 1 cup (200 g) | 18 g |
| Greek yoghurt | 170 g | 17 g |
| Laban / milk | 250 ml | 8 g |
Frequently asked questions
Can I eat too much protein?
Intakes up to about 2 g/kg a day are well studied in healthy adults. People with kidney disease should follow their doctor's advice on protein.
Should I spread protein across meals?
Studies on muscle building suggest dividing it over three or four meals of roughly 0.3–0.4 g/kg each works well.
Do I use my current weight?
For most people, yes. If you carry a lot of body fat, base it on a healthy weight for your height instead.
How much protein is in common foods?
Roughly: 100 g of cooked chicken breast has about 31 g, one large egg about 6 g, and 100 g of cooked lentils about 9 g. Check labels for packaged foods.
Do I need protein powder?
No. It is simply a convenient source. If food already gets you to your target, powder adds nothing extra.
Do older adults need more protein?
Many experts suggest about 1.0 to 1.2 g per kg for people over 65, to help keep muscle. If you have kidney disease, ask your doctor first.