How much protein do you need a day?
A healthy adult needs at least 0.83 g of protein per kilogram of body weight a day (EFSA), which is about 58 g for 70 kg.
If you train regularly, the recommendation rises to 1.4–2.0 g/kg (ISSN), and when you are losing weight or building muscle, to 1.6–2.2 g/kg.
How are protein needs calculated?
Protein needs are calculated by multiplying body weight by a number of grams per kilogram, chosen for your activity and goal. The calculator shows a range, because the sources give ranges, not a single number.
Over 65, the minimum rises to 1.0 g/kg, following the PROT-AGE group recommendation, to limit the loss of muscle mass with age.
Formula
- Protein (g/day) = weight (kg) × need (g/kg/day)
- Need: 0.83 (EFSA) up to 2.2 g/kg/day, depending on activity and goal
Worked example
A 70 kg person who trains regularly and wants to lose weight: 70 × 1.6 = 112 g and 70 × 2.2 = 154 g, so about 110–155 g of protein a day. The EFSA minimum for the same weight would be 58 g.
How many grams of protein per kilogram, by situation?
| Situation | g/kg per day | For 70 kg |
|---|---|---|
| EFSA reference for adults | 0.83 | 58 g |
| Sedentary, maintenance | 0.83–1.0 | 58–70 g |
| Occasionally active, maintenance | 1.0–1.2 | 70–84 g |
| Weight loss (calorie deficit) | 1.2–1.6 | 84–112 g |
| Regular training, maintenance | 1.4–2.0 | 98–140 g |
| Training plus weight loss or muscle gain | 1.6–2.2 | 112–154 g |
| Over 65 (minimum) | 1.0 | 70 g |
What does this calculator not take into account?
- It uses total body weight. With obesity the result may be too high; a specialist can calculate from goal weight or lean mass.
- It does not apply during pregnancy and breastfeeding, where EFSA recommends extra amounts, or to children.
- Above about 1.6 g/kg, the benefit for muscle mass grows only a little (Morton et al., 2018); more is not automatically better.
- How you split it matters too: 20–40 g portions over 3–4 meals are used better than everything in one meal (ISSN).
When should you talk to a specialist?
If you have kidney or liver disease, or diabetes with kidney complications, do not increase your protein without talking to your doctor: in these cases the amount is set individually.
A dietitian can also help if you follow a vegetarian or vegan diet and are not sure how to cover your needs.
Working with a nutritionist? See how they follow you in Rod