How much protein do you need at 100 lb?
At 100 lb (45 kg), aim for 36 g a day to stay healthy, and 73 to 100 g to build muscle.
Updated October 2026
Daily protein at 100 lb by goal
| Goal | Per day | Per meal (4 meals) |
|---|---|---|
| General health | 36 g | 9 g |
| Adults over 65 | 45 to 54 g | 11 to 14 g |
| Active, regular exercise | 54 to 73 g | 14 to 18 g |
| Building muscle | 73 to 100 g | 18 to 25 g |
| Losing fat and keeping muscle | 82 to 109 g | 20 to 27 g |
Foods that add up to 73 g
How many servings of each food it takes to reach 73 g, the low end for building muscle.
| Food | Serving | Protein | Servings for 73 g |
|---|---|---|---|
| Chicken breast, cooked | 100 g (3.5 oz) | 31 g | 2.4 |
| Canned tuna, drained | 100 g (3.5 oz) | 25 g | 2.9 |
| Salmon, cooked | 100 g (3.5 oz) | 22 g | 3.3 |
| Lean beef mince, cooked | 100 g (3.5 oz) | 26 g | 2.8 |
| Greek yogurt, plain | 170 g (6 oz) pot | 17 g | 4.3 |
| Cottage cheese | 1 cup (220 g) | 25 g | 2.9 |
| Eggs | 1 large egg | 6 g | 12.2 |
| Milk | 1 cup (240 ml) | 8 g | 9.1 |
| Lentils, cooked | 1 cup (200 g) | 18 g | 4.1 |
| Chickpeas, cooked | 1 cup (160 g) | 15 g | 4.9 |
| Firm tofu | 100 g (3.5 oz) | 10 g | 7.3 |
| Peanut butter | 2 tbsp (32 g) | 7 g | 10.4 |
Other weights
Questions
How much protein should a 100 lb person eat a day?
For general health, about 36 g a day (0.8 g per kg). For regular exercise, 54 to 73 g. For building muscle, 73 to 100 g.
How much protein do I need to build muscle at 100 lb?
73 to 100 g a day, which is 1.6 to 2.2 g per kg of body weight. At 45 kg that works out to 73 g at the low end.
How much protein do I need to lose fat at 100 lb?
82 to 109 g a day while lifting weights in a calorie deficit. The higher end helps you keep muscle.
What does 73 g of protein look like in food?
About 235 g of cooked chicken breast, or 12 large eggs, or a mix across the day. A 100 g portion of cooked chicken breast has about 31 g and a large egg about 6 g.
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