Protein guide
Protein Sources: A Complete Reference
Protein per serving, per 100 g, per calorie, and digestibility scores for 30+ animal and plant foods — the data behind every calculator recommendation.
Your daily protein target is only useful if you can hit it with real food. This reference lists the protein content, calories, and quality of the most common animal and plant protein sources, so you can build meals that add up to your goal without guesswork.
All values are approximate, drawn from the USDA FoodData Central database and rounded for readability. Cooked weights are used for meats, fish, and legumes because that is how most people actually eat them. Where a serving size varies (a scoop, a cup, a handful), we list the gram weight so you can scale it.
Animal-based protein sources
Animal proteins are complete — they contain all nine essential amino acids in amounts your body can use — and they score highest on digestibility measures. They are also the most protein-dense per calorie when you choose lean cuts.
| Food | Serving | Protein | g / 100 g | kcal / serving | Notes |
|---|---|---|---|---|---|
| Chicken breast | 100 g cooked | 31 g | 31 | 165 | Lean, versatile, highest protein-to-calorie ratio of common meats |
| Turkey breast | 100 g cooked | 30 g | 30 | 189 | Similar to chicken; slightly richer in tryptophan |
| Lean beef (sirloin) | 100 g cooked | 26 g | 26 | 206 | Rich in iron, zinc, and vitamin B12 |
| Pork tenderloin | 100 g cooked | 26 g | 26 | 143 | As lean as chicken breast when trimmed |
| Tuna (canned in water) | 100 g drained | 24 g | 24 | 116 | Convenient, shelf-stable, very low fat |
| Salmon | 100 g cooked | 22 g | 22 | 208 | High in omega-3 fats; higher in calories |
| Shrimp | 100 g cooked | 24 g | 24 | 99 | Very low calorie, high protein |
| Cod | 100 g cooked | 18 g | 18 | 82 | Extremely lean white fish |
| Large eggs | 1 large (50 g) | 6 g | 13 | 78 | Reference protein; PDCAAS of 1.0 |
| Greek yogurt (nonfat) | 170 g (¾ cup) | 17 g | 10 | 100 | Casein-rich; slow-digesting |
| Cottage cheese (low-fat) | 1 cup (226 g) | 25 g | 11 | 163 | High casein; very filling |
| Cow milk (2%) | 1 cup (244 g) | 8 g | 3.4 | 122 | Liquid protein; easy to add |
Plant-based protein sources
Plant proteins can absolutely meet high targets, but most (except soy, quinoa, and hemp) are missing or low in at least one essential amino acid. The fix is simple: combine legumes with grains across the day — rice and beans, hummus and pita, lentils and rice — to round out the amino acid profile.
| Food | Serving | Protein | g / 100 g | kcal / serving | Notes |
|---|---|---|---|---|---|
| Firm tofu | 100 g | 12 g | 12 | 144 | Complete plant protein; absorbs flavor well |
| Tempeh | 100 g | 19 g | 19 | 192 | Fermented soy; high in fiber |
| Seitan (vital wheat gluten) | 100 g | 25 g | 25 | 148 | Densest plant protein; not gluten-free |
| Edamame | 100 g cooked | 11 g | 11 | 121 | Whole soy; high in folate |
| Lentils | 1 cup cooked (198 g) | 18 g | 9 | 230 | High fiber and folate |
| Chickpeas | 1 cup cooked (164 g) | 15 g | 9 | 269 | Versatile; basis of hummus |
| Black beans | 1 cup cooked (172 g) | 15 g | 9 | 227 | High fiber and iron |
| Peanuts | 28 g (≈28 nuts) | 7 g | 26 | 161 | Technically a legume; calorie-dense |
| Almonds | 28 g (≈23 nuts) | 6 g | 21 | 164 | High in vitamin E and magnesium |
| Pumpkin seeds | 28 g | 8 g | 30 | 151 | Rich in zinc and magnesium |
| Hemp seeds | 28 g | 9 g | 31 | 155 | Complete protein; high in omega-3 |
| Chia seeds | 28 g | 5 g | 17 | 137 | High in fiber and ALA |
| Quinoa | 1 cup cooked (185 g) | 8 g | 4 | 222 | Complete protein grain |
| Green peas | 1 cup cooked (160 g) | 8 g | 5 | 134 | Higher protein than most vegetables |
Protein powders and supplements
Powders are convenient, not essential. They help when you struggle to hit a high target from food alone, when you need something portable after training, or when you want to add protein to oats or smoothies without many extra calories. Per 100 g of powder they look extremely protein-dense, but remember a typical scoop is only 30 g.
| Supplement | g / 100 g | Per scoop | Notes |
|---|---|---|---|
| Whey protein concentrate | 80 | 24 g (30 g scoop) | Fast-absorbing; PDCAAS 1.0; highest leucine |
| Whey protein isolate | 90 | 27 g (30 g scoop) | Lower lactose and fat than concentrate |
| Casein | 80 | 24 g (30 g scoop) | Slow-digesting; popular before sleep |
| Soy protein isolate | 80 | 24 g (30 g scoop) | Complete plant protein; PDCAAS 1.0 |
| Pea protein | 75 | 22 g (30 g scoop) | Lower in methionine; pair with rice protein |
Protein quality: digestibility explained
Not all protein grams are equal. Two scores matter: PDCAAS (Protein Digestibility Corrected Amino Acid Score) and the newer DIAAS (Digestible Indispensable Amino Acid Score). Both measure how well your body can actually use the protein. A score of 1.0 (or above, for DIAAS) means the protein is fully usable; lower scores mean you need to eat more total grams to get the same usable protein.
| Source | PDCAAS | DIAAS | Notes |
|---|---|---|---|
| Whey protein | 1.00 | 1.09 | Reference standard; fast absorption |
| Egg | 1.00 | 1.13 | Whole-food reference protein |
| Cow milk | 1.00 | 1.18 | Highest DIAAS of common foods |
| Beef | 0.92 | 1.11 | Rich in heme iron and B12 |
| Chicken | 0.95 | 1.08 | High-quality animal protein |
| Soy | 0.91 | 0.91 | Best-scoring plant protein |
| Pea | 0.69 | 0.73 | Lower in methionine |
| Wheat gluten | 0.42 | 0.54 | Low in lysine; high total protein |
| Beans | 0.68 | 0.65 | Low in methionine; high fiber |
This is exactly why our calculator adds 5% for vegetarian and 10% for vegan diets: the lower digestibility of most plant proteins means you need slightly more total grams to get the same usable protein.
How to choose your protein sources
A simple framework:
- • For most protein per calorie: lean chicken, turkey, white fish, shrimp, nonfat Greek yogurt.
- • For convenience: canned tuna, Greek yogurt, eggs, cottage cheese, whey protein.
- • For plant-based: tofu, tempeh, seitan, lentils, edamame — combine legumes with grains across the day.
- • For budget: eggs, lentils, canned tuna, milk, chicken thighs, peanut butter.
- • For satiety: casein-rich foods (cottage cheese, Greek yogurt) and high-fiber plant proteins (lentils, beans).
Variety matters more than any single "best" source. Rotating between animal and plant proteins, lean and fatty fish, and whole foods plus the occasional supplement gives you a broader micronutrient intake and keeps meals interesting enough to stick with long term.
Ready to find your daily target?
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