The highest protein per calorie comes from shellfish, white fish, egg whites, poultry breast, and nonfat dairy. They land at roughly 17 to 24 grams of protein for every 100 calories. Whey protein isolate powder sits in the same range, depending on the label.
The ratio is simple. Take the grams of protein, divide by the calories, and scale it to 100 calories so every food gets the same denominator. Shrimp and a slice of cheese can then be compared on one line.
Which foods have the highest protein per calorie?
The ranked table: grams of protein per 100 calories
Every whole-food figure below comes from USDA FoodData Central, using the Foundation and SR Legacy entries. The whey isolate row is the exception. It uses a representative label from the branded entries, because powders vary by product. Cooked or raw is stated, because it changes the per-gram numbers (more on that below).
| Rank | Food | Calories per 100 g | Protein per 100 g | Protein per 100 calories | % of calories from protein |
|---|---|---|---|---|---|
| 1 | Shrimp, cooked | 99 | 24.0 g | 24.2 g | 97% |
| 2 | Whey protein isolate powder (representative label) | about 370 | about 88 g | about 24 g | about 95% |
| 3 | Light tuna, canned in water, drained | 116 | 25.5 g | 22.0 g | 88% |
| 4 | Atlantic cod, cooked | 105 | 22.8 g | 21.7 g | 87% |
| 5 | Egg white, raw | 52 | 10.9 g | 21.0 g | 84% |
| 6 | Tilapia, cooked | 128 | 26.2 g | 20.5 g | 82% |
| 7 | Chicken breast, skinless, roasted | 165 | 31.0 g | 18.8 g | 75% |
| 8 | Greek yogurt, plain, nonfat | 59 | 10.2 g | 17.3 g | 69% |
| 9 | Cottage cheese, 1% milkfat | 72 | 12.4 g | 17.2 g | 69% |
| 10 | Tofu, firm, calcium-set, raw | 144 | 17.3 g | 12.0 g | 48% |
| 11 | Tempeh | 192 | 20.3 g | 10.6 g | 42% |
| 12 | Skim milk | 34 | 3.4 g | 9.9 g | 40% |
| 13 | Whole egg, raw | 143 | 12.6 g | 8.8 g | 35% |
| 14 | Lentils, boiled | 116 | 9.0 g | 7.8 g | 31% |
Tofu varies more than anything else on the list. Firmness and the coagulant change the water content, so check the package you actually bought.
The last column is arithmetic you can check. Protein carries about 4 calories per gram. Multiply grams of protein by 4, divide by total calories, and you get the share of calories from protein.
Worked example with cod: 22.8 g times 4 is 91.2 calories. Divide by 105 and you get 0.87, or 87 percent. USDA uses food-specific calorie factors rather than a flat 4, so your result may differ from a published figure by a point or two.
One row is not like the others. A powder has no water in it, so a scoop is protein with the water already removed. That is why an isolate keeps pace with shrimp. It is also why powder is compared per scoop and not per 100 g. Nobody eats 100 g of it.
What the top of the list has in common
The whole foods at the top have almost no fat. They are mostly water and protein, and water has no calories. Shrimp, cod, and egg white are close to pure protein once you take the water out of the picture.
Fat carries about 9 calories per gram, so any food with fat in it slides down. That's why the whole egg sits at 8.8 while the white alone sits at 21.0. The yolk did nothing wrong. It just carries fat, and fat is expensive in calories.
This is arithmetic, not a verdict. The ratio is just division, and it works the same on a fillet, a yogurt or a packaged serving.
What does the denominator hide?
Per 100 g, per serving, per 100 calories
The denominator is the number you divide by. A protein figure on a label means nothing until you know what it was divided by: a weight, a serving, or a count of calories. Change the denominator and the same food tells a different story.
| Food | Protein per 100 g | Protein per serving as labeled | Protein per 100 calories |
|---|---|---|---|
| Chicken breast, roasted | 31.0 g | 26.4 g per 85 g (140 cal) | 18.8 g |
| Greek yogurt, nonfat | 10.2 g | 17.3 g per 170 g (100 cal) | 17.3 g |
| Almonds | 21.2 g | 6.0 g per 28 g (164 cal) | 3.7 g |
| Typical protein bar (60 g, 220 cal) | about 33 g | 20 g | about 9 g |
| Typical ready-to-drink shake (330 mL, 160 cal) | about 9 g (per 100 mL) | 30 g | about 19 g |
Per 100 g rewards dryness and punishes water. Almonds look stronger than yogurt per gram, then come out at less than a quarter of yogurt per calorie. Skim milk looks weak at 3.4 g per 100 g, then reaches 9.9 g per 100 calories, ahead of a whole egg. The bar looks better per gram than the shake, then the shake wins per calorie by double.
The rule is short. Compare across foods per 100 calories. Compare within one food per serving, because that's the amount you're eating.
The serving size is picked by the manufacturer, within limits set by regulators, not by you. It is worth knowing who chose the denominator.
Category arithmetic, with no brands, from representative labels in the USDA FoodData Central branded foods data:
- Bars: many run about 180 to 250 calories for 15 to 20 g of protein. Most land around 7 to 10 g per 100 calories.
- Ready-to-drink shakes: many run 150 to 200 calories for 20 to 30 g. That works out to roughly 10 to 20 g per 100 calories.
- Powders: scoop sizes vary. Isolates usually come out around 20 to 25 g per 100 calories, while blends and concentrates sit lower.
The three-second check: divide protein by calories, multiply by 100. A bar with 20 g and 220 calories is 9.1. Done.
| Label (hypothetical bars) | Protein | Calories | Protein per 100 calories |
|---|---|---|---|
| Bar A | 20 g | 220 | 9.1 g |
| Bar B | 15 g | 180 | 8.3 g |
| Bar C | 20 g | 180 | 11.1 g |
Bars A and C both say 20 g on the front. One is 9.1 and the other is 11.1. Twenty grams on the front of the pack is a number. The calories next to it are the rest of the sentence.
Raw weight, cooked weight, and water
Cooking moves the per-gram numbers without changing the food. Raw skinless chicken breast is about 120 calories and 22.5 g of protein per 100 g. Roasted, it's 165 calories and 31.0 g per 100 g. The breast lost water in the oven, so each remaining gram is denser. The total protein in the piece stayed the same.
Now check the ratio. Raw: 22.5 divided by 120, times 100, is 18.8. Cooked: 31.0 divided by 165, times 100, is 18.8. Same number.
Water changes the weight, not the protein or the calories. Per 100 calories is the one figure that doesn't care whether you weighed the food before or after the pan.
What counts as high protein on a label?
The regulatory definitions, stated plainly
"High protein" on a package is a legal threshold, not a description. The threshold depends on where the food is sold.
In the US, "high protein" means the food provides 20 percent or more of the Daily Value per serving. The Daily Value for protein is 50 g, so "high protein" means 10 g or more per labeled serving. "Good source of protein" means 10 to 19 percent of the Daily Value, or 5 to 9.5 g.
When a protein claim is made, the US label also has to show a percent Daily Value corrected for protein quality using PDCAAS, the protein digestibility-corrected amino acid score. That is a number that discounts protein the body digests or uses less well.
"Low calorie" in the US means 40 calories or fewer per serving. Technically that is per reference amount, the standard portion the rules assign to that food type.
In the EU, "high protein" means at least 20 percent of the food's energy comes from protein. "Source of protein" means at least 12 percent. The EU's version of "low calorie," called "low energy," is 40 calories or fewer per 100 g for solids and 20 per 100 mL for liquids.
| Region | Claim | Threshold | Denominator |
|---|---|---|---|
| US | High protein | 10 g or more (20% DV) | Per serving |
| US | Good source of protein | 5 to 9.5 g (10 to 19% DV) | Per serving |
| US | Low calorie | 40 calories or fewer | Per serving (reference amount) |
| EU | High protein | 20% or more of energy from protein | Share of total calories |
| EU | Source of protein | 12% or more of energy from protein | Share of total calories |
| EU | Low energy | 40 cal per 100 g (solids), 20 per 100 mL (liquids) | Per weight or volume |
Why a claim and a ratio are different things
The useful asymmetry: the EU claim is a ratio and the US claim is an amount.
Take a 400-calorie product with 10 g of protein. In the US, assuming a full-quality protein, it can say "high protein." In the EU, 10 g times 4 is 40 calories, which is 10 percent of energy. It doesn't even reach "source of protein."
Now take a 100-calorie product with 5 g. In the US it is a "good source," not "high." In the EU, 5 g times 4 is 20 calories, which is exactly 20 percent of energy. It qualifies as "high protein." The smaller, less impressive-looking product wins under one rulebook and loses under the other.
Neither claim says anything about the ingredient list. A claim tells you a threshold was cleared. It does not tell you by how much, or with what.
Is a gram of protein the same in every food?
Protein quality: what the ratio does not measure
The ratio counts grams. It does not say how well your body can use them. That second question is protein quality: how well a food supplies the essential amino acids.
"Essential" is a technical word here, and it doesn't mean "important." It means the body cannot make that amino acid, so it has to come from food. Non-essential amino acids are ones the body can make on its own. They are not useless. They are just not required on the plate.
The current scoring method is DIAAS, the digestible indispensable amino acid score. "Indispensable" is another word for essential. DIAAS measures how much of each essential amino acid is actually absorbed, compared with what the body needs, and the food's score is set by the amino acid that falls shortest.
A 2025 review by Matthews, Arentson-Lantz, and Moughan in the Journal of Nutrition lays out the method and its limits. Animal proteins such as egg, dairy, and fish generally score high. Many plant proteins score lower on one or more amino acids.
A label counts a gram of gelatin and a gram of egg white the same way. Your body sends them to different jobs.
- Complete protein: supplies all nine essential amino acids in useful amounts. Example: egg white.
- Incomplete protein: short on at least one. Example: collagen, and gelatin made from it, which lack tryptophan entirely. Collagen can show a respectable gram count and still not be a complete protein.
Legumes: lower ratio, different strengths
Lentils sit at 7.8 g per 100 calories, near the bottom of the table. That's because they're mostly carbohydrate, and some of that carbohydrate is fiber. The ratio doesn't count the fiber. The ratio is one column. It is not the whole food.
Plant protein digestibility is not a guess. It can be measured directly in people. Itkonen and colleagues (2024) fed healthy adults faba beans labeled with a traceable form of nitrogen and measured how much of each amino acid was absorbed by the end of the small intestine.
The result was specific to faba bean, amino acid by amino acid. It's one legume, and it doesn't speak for lentils, chickpeas, or soy.
How much plant versus animal protein makes the best mix is still open. A 2024 analysis of three large cohorts by Glenn et al. looked at the plant-to-animal protein ratio. It is an observational study, not a final answer.
What does protein per calorie look like across a meal?
Per meal arithmetic
A meal's ratio is not the average of its foods' ratios. Add up the protein, add up the calories, then divide. Bigger portions pull harder on the result.
| Meal | Total calories | Total protein | Protein per 100 calories |
|---|---|---|---|
| 2 whole eggs (100 g) + 1 slice whole wheat toast | 143 + 80 = 223 | 12.6 + 4 = 16.6 g | 16.6 ÷ 223 × 100 = 7.4 g |
| Same, plus 100 g egg whites | 223 + 52 = 275 | 16.6 + 10.9 = 27.5 g | 27.5 ÷ 275 × 100 = 10.0 g |
| 200 g cooked lentils + 170 g nonfat Greek yogurt | 232 + 100 = 332 | 18.0 + 17.3 = 35.3 g | 35.3 ÷ 332 × 100 = 10.6 g |
| 1 scoop whey isolate + 1 medium banana | 110 + 105 = 215 | 25 + 1.3 = 26.3 g | 26.3 ÷ 215 × 100 = 12.2 g |
Egg, lentil, yogurt, and banana figures are from USDA FoodData Central. The toast and the scoop are representative labels, so swap in your own.
The per-meal comparison is pure arithmetic. Twenty-five grams in 150 calories is 16.7 g per 100 calories. Twenty-five grams in 400 calories is 6.25. Same protein, very different denominator.
Who cares about this? People who eat less overall, people who skip lunch, and people who train hard and want protein without much else riding along. When a meal has fewer calories in it, each calorie has to carry more of the protein for the total to add up. That's a reason to check the number, not an instruction to change anything.
The thirty-gram-per-meal rule tends to come up here. It gets repeated with more confidence than the evidence carries. The research on a per-meal ceiling is mixed, and no single number has earned the certainty it gets in conversation.
Mixing high-ratio and lower-ratio foods
A low-ratio food is still a fine food. Whole eggs, lentils, tempeh, and milk sit lower on the table because they carry fat, carbohydrate, or fiber alongside the protein. That's what they are, not a flaw.
Mixing works because a meal's ratio is one sum. Add 100 g of egg whites to two whole eggs and the meal moves from 7.4 to 10.0 without losing the yolks. Add yogurt to lentils and the bowl reaches 10.6 while keeping the fiber. One high-ratio food lifts the whole plate.
The same sum works with a packaged serving, as long as you read its ratio the same way: grams divided by calories, nothing else.
The short version
- Shrimp, isolate powder, tuna, cod, egg white, tilapia, chicken breast, nonfat Greek yogurt, and cottage cheese: about 17 to 24 g per 100 calories.
- Firm tofu and tempeh: about 10 to 12.
- Skim milk and whole eggs: about 9 to 10.
- Bars: mostly 7 to 10.
- Lentils: about 8.
The check takes three seconds. Divide protein by calories and multiply by 100.
Use per 100 calories to compare foods. Use per serving to compare within one food. A label claim like "high protein" is a threshold: 10 g per serving in the US, 20 percent of energy in the EU. It is not a ratio, and the two rules can disagree about the same product.
The limit, once: the ratio counts grams, not quality. Egg white and gelatin can share a number and not a score.
It's division. The label already did half of it.
Frequently Asked Questions
Which foods have the most protein per calorie?
Shellfish, white fish, egg whites, poultry breast, and nonfat dairy give about 17 to 24 grams of protein per 100 calories. Cooked shrimp is highest among whole foods at about 24.2 g, followed by canned light tuna, cod, and egg white. Whey protein isolate powder falls in the same range, depending on the label.
How do you calculate protein per 100 calories?
Divide the grams of protein by the calories, then multiply by 100. A bar with 20 g of protein and 220 calories works out to 9.1 g per 100 calories. This puts every food on the same denominator, so a bar and a piece of fish can be compared directly.
Does cooking change the protein per calorie of a food?
No, the ratio stays the same. Raw skinless chicken breast has about 22.5 g of protein and 120 calories per 100 g, and roasted it has 31.0 g and 165 calories, so both come to 18.8 g per 100 calories. Cooking removes water, which changes the per-gram numbers but not the ratio.
What does "high protein" mean on a food label?
In the US, "high protein" means 10 g or more per serving, which is 20 percent of the 50 g Daily Value. In the EU, it means at least 20 percent of the food's calories come from protein. The US rule is an amount and the EU rule is a ratio, so the same product can qualify under one and not the other.
Is a gram of protein the same in every food?
No, because foods differ in how well they supply essential amino acids and how well the body absorbs them. Egg white is a complete protein, while collagen and gelatin lack tryptophan entirely, yet both can show similar gram counts on a label. The current scoring method is DIAAS, laid out in a 2025 review by Matthews, Arentson-Lantz, and Moughan.
Are protein bars a good source of protein per calorie?
Most bars are modest on this measure, at about 7 to 10 g of protein per 100 calories. Ready-to-drink shakes often reach roughly 10 to 20 g, and isolate powders about 20 to 25 g. Two bars can both say 20 g on the front and still differ: 220 calories gives 9.1 g per 100 calories, and 180 calories gives 11.1 g.