How Much Protein for a 55 kg (121 lb) Person?
110 g a day to build muscle (2 g per kg, or about 0.91 g per lb). To lose fat the target is 121 g; to maintain your weight it is 66 g.
Assumes a 30-year-old with a moderate activity level and 3 training days a week. Use the protein calculator for your own numbers.
Daily protein for 55 kg by goal
| Goal | Target per day | Range per day | Per meal (4 meals) | Calories from protein |
|---|---|---|---|---|
| Build muscle | 110 g (2 g/kg) | 88–121 g | 28 g | 440 kcal |
| Lose fat | 121 g (2.2 g/kg) | 88–154 g | 30 g | 484 kcal |
| Athletic performance | 99 g (1.8 g/kg) | 77–110 g | 25 g | 396 kcal |
| Maintain weight | 66 g (1.2 g/kg) | 44–88 g | 17 g | 264 kcal |
The target is the middle of the evidence-based range for each goal. Calories from protein use 4 kcal per gram. Basis: ISSN 2017: 1.4-2.0 g/kg is enough for most exercising people; Morton 2018: gains level off near 1.6 g/kg.
The arithmetic, step by step
Here is how the muscle-building number for 55 kg is worked out, so you can check it.
- Body weight times grams per kilogram: 55 kg × 2 g = 110 g a day.
- Split over 4 meals: 110 g ÷ 4 = about 28 g per meal.
- Calories from that protein: 110 g × 4 kcal = 440 kcal.
- In pounds: 55 kg is 121 lb, so 110 g is about 0.91 g per pound of body weight.
Swap in the fat-loss rate of 2.2 g per kg and the same sum gives 121 g; at the maintenance rate of 1.2 g per kg it gives 66 g.
How training changes it (muscle-building goal)
The same 55 kg person needs more protein as training volume rises. These examples keep the goal as building muscle and change only activity and training days.
| Activity | Target per day | Range per day |
|---|---|---|
| Sedentary, no training | 94 g (1.7 g/kg) | 80–121 g |
| Light activity, 2 training days | 105 g (1.9 g/kg) | 85–121 g |
| Moderate activity, 3 training days | 110 g (2 g/kg) | 88–121 g |
| High activity, 5 training days | 110 g (2 g/kg) | 94–121 g |
| Athlete, 6 training days | 110 g (2 g/kg) | 99–121 g |
Does age change the number?
Yes, from about 50. Older adults respond less to the same dose of protein, so the calculator adds a little for age 50 and over and a little more from 65. For a 55 kg person building muscle at a moderate activity level:
- At age 30: 110 g a day (2 g/kg)
- At age 55: 110 g a day (2 g/kg)
- At age 70: 110 g a day (2 g/kg)
Protein for 55 kg: common questions
How much protein should a 55 kg person eat per day?
It depends on the goal. For a 55 kg (121 lb) person with a moderate activity level and 3 training days a week, the calculator suggests about 110 g a day to build muscle (range 88–121 g), 121 g to lose fat, and 66 g to maintain weight.
How much protein per meal for 55 kg?
Split over 4 meals, the muscle-building target of 110 g works out to about 28 g per meal. The fat-loss target of 121 g is about 30 g per meal.
How many grams of protein per pound is that for 121 lb?
The muscle-building target of 2 g per kg is about 0.91 g per pound of body weight. For 121 lb that is roughly 110 g a day.
Other body weights
General information, not medical advice. People with kidney disease or other medical conditions should ask a doctor or dietitian first. See the disclaimer.