Protein Calculator
Find out exactly how many grams of protein you need per day. Protein is the #1 macronutrient for fat loss, muscle building, and staying full between meals.
The Science of Protein Intake
Protein is made up of amino acids — the building blocks your body uses to repair muscle tissue, produce enzymes and hormones, support immune function, and maintain healthy skin, hair, and nails. Of the 20 amino acids, 9 are "essential" — your body can't make them, so you must get them from food.
The old RDA (Recommended Daily Allowance) of 0.36g per pound of body weight was established to prevent deficiency in sedentary people — not to optimize body composition or athletic performance. Modern sports nutrition research consistently shows that active individuals need 2-3x this amount for optimal results.
Protein for Fat Loss
During a calorie deficit, your body breaks down both fat and muscle for energy. The single most effective way to preserve muscle while losing fat is to eat adequate protein. A 2016 study in the American Journal of Clinical Nutrition found that participants eating 1.1g of protein per pound while in a 40% calorie deficit actually gained lean mass while losing fat — a phenomenon called body recomposition.
Protein also has a thermic effect of 20-30%, meaning your body burns 20-30% of protein calories just digesting and processing it. Compare this to carbs (5-10%) and fat (0-3%). Eating 200g of protein effectively "costs" your body 40-60 more calories in digestion than eating 200g of carbs.
Protein for Muscle Building
Muscle protein synthesis (MPS) — the process of building new muscle — is stimulated by both resistance training and protein intake. Research shows that MPS is maximized at about 0.4g of protein per kg of body weight per meal (roughly 25-40g for most people). Eating more than this in a single sitting doesn't increase MPS further, which is why spreading protein across 4-5 meals is more effective than loading it all into one or two meals.
High Protein Foods Ranked by Protein-per-Calorie
| Food | Protein | Calories | Protein/Cal |
|---|---|---|---|
| Chicken breast (4oz) | 31g | 130 | 24% |
| Egg whites (1 cup) | 26g | 120 | 22% |
| Shrimp (4oz) | 24g | 120 | 20% |
| Greek yogurt (1 cup) | 17g | 100 | 17% |
| Tuna (3oz can) | 16g | 70 | 23% |
| Cottage cheese (1/2 cup) | 14g | 90 | 16% |
| Whey protein (1 scoop) | 25g | 120 | 21% |
| Turkey breast (4oz) | 28g | 120 | 23% |
| Salmon (4oz) | 25g | 200 | 13% |
| Tofu, firm (4oz) | 10g | 90 | 11% |
FAQ
How much protein do I need per day?
For most active adults, 0.7-1.0 grams per pound of body weight is optimal. If you're trying to lose fat while preserving muscle, aim for 0.8-1.2g per pound. For muscle building, 0.9-1.3g per pound. A 170 lb person building muscle should eat 153-221g of protein per day.
Can you eat too much protein?
For healthy adults with normal kidney function, high protein intake (up to 1.5g per pound) has been shown to be safe in multiple long-term studies. The idea that high protein damages kidneys is a myth — it only applies to people with pre-existing kidney disease. That said, protein beyond 1.3g per pound doesn't provide additional muscle-building benefits.
What's the best protein source?
The best protein source is the one you'll consistently eat. That said, complete proteins containing all essential amino acids are ideal: chicken, fish, eggs, dairy, and beef. For plant-based eaters, combining legumes with grains (rice and beans) provides all essential amino acids. Whey protein is the most researched supplement and is excellent for convenience.
When should I eat protein?
Distribute protein evenly across 3-5 meals, aiming for 25-40g per meal. This maximizes muscle protein synthesis throughout the day. Post-workout protein (within 2 hours) is beneficial but the 'anabolic window' is much larger than the old 30-minute myth. Getting enough total daily protein matters far more than timing.
Does protein help with weight loss?
Yes — protein is the most important macronutrient for weight loss for three reasons: (1) It's the most satiating macro, keeping you fuller on fewer calories. (2) It has the highest thermic effect — your body burns 20-30% of protein calories just digesting it. (3) It preserves muscle mass during a calorie deficit, ensuring you lose fat, not muscle.
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