Aged cheese can be very high in protein per 100 grams, and almonds provide more than 20 grams. But ask a different question — how much protein do I get for a fixed number of calories? — and the leaderboard changes. Foods that are high in protein and low in fat, such as lean fish, egg whites and poultry, move up fast.
This metric does not tell you which food is “best.” It answers one specific question, which makes it useful when the goal is to raise protein without raising total energy at the same pace.
Protein for every 100 calories
| Food | Protein/100 g | Calories/100 g | Protein/100 cal |
|---|---|---|---|
| Cooked yellowfin tuna | 29.2 g | 130 | 22.4 g |
| Cooked cod | 22.8 g | 105 | 21.7 g |
| Egg whites | 10.9 g | 52 | 21.0 g |
| Cooked turkey breast | 29.5 g | 145 | 20.3 g |
| Cooked chicken breast | 31.0 g | 165 | 18.8 g |
| Plain nonfat Greek yogurt | ~10 g | ~59 | ~17 g |
| Low-fat cottage cheese | ~11.5 g | ~85 | ~13.5 g |
| Firm tofu | ~15 g | ~145 | ~10.3 g |
| Cooked lentils | 9.0 g | 116 | 7.8 g |
Cod shows why the ranking changes
Yellowfin tuna provides about 29.2 g protein for 130 calories per 100 g. Cod provides 22.8 g for 105 calories. Because both are relatively lean, a large share of their energy comes from protein.
Chicken breast contains more protein by weight than cod —31 versus 22.8 g/100 g— but also more calories —165 versus 105. So cod comes out slightly ahead when the denominator is calories instead of grams. Two rankings, two different questions.
Egg whites are mostly protein and water
Egg whites provide about 10.9 g protein and 52 calories/100 g, while whole egg is around 12.6 g protein and 143 calories. The difference is not that the yolk is “bad”: yolks add fat, choline and many vitamins and minerals.
Removing the yolk improves protein efficiency, but it also removes much of what makes an egg nutritionally distinctive. The better choice depends on what that meal needs.
Turkey and chicken are close, not worlds apart
Cooked turkey breast is about 29.5 g protein and 145 calories/100 g; chicken breast about 31 g and 165 calories. A 5-ounce / 142 g serving gives roughly 42 g protein and 206 calories from turkey versus 44 g and 234 calories from chicken.
Chicken gives a little more protein; turkey gives almost as much for a little less energy. The difference is real but small.
High-protein dairy can be efficient — labels matter
Plain nonfat Greek yogurt can provide around 10 g protein and 59 calories/100 g. A 6-ounce / 170 g container is therefore around 17 g protein and 100 calories.
But “Greek-style” is not a fixed nutrition profile. Full-fat or sweetened products can carry two or three times the calories of a plain nonfat version without multiplying the protein in the same way.
Plant foods tell a different nutrition story
Firm tofu, seitan and soy foods can provide a useful amount of protein for their calories. Lentils supply 9 g protein and 116 calories/100 g — less protein efficiency than cod, but nearly 8 g fiber that cod does not provide.
Almonds make the limitation especially obvious: about 21.2 g protein and 579 calories/100 g, compared with 22.8 g and 105 calories for cod. Nearly the same protein by weight, more than five times the energy. The almonds also bring fiber, vitamin E, magnesium and unsaturated fat, none of which appears in a protein-per-calorie score.
What this looks like by serving
| Food | Serving | Protein | Calories |
|---|---|---|---|
| Cod | 5 oz / 142 g | 32 g | 149 |
| Turkey breast | 5 oz / 142 g | 42 g | 206 |
| Chicken breast | 5 oz / 142 g | 44 g | 234 |
| Nonfat Greek yogurt | 6 oz / 170 g | ~17 g | ~100 |
| Cooked lentils | 1 cup / ~200 g | 18 g | 232 |
What the metric cannot see
Protein per calorie is useful when total energy matters, but it does not score fiber, essential fats, vitamins or minerals. Salmon ranks below cod because it contains more fat and roughly 206 calories/100 g instead of 105, yet that fat includes valuable EPA and DHA omega-3s.
So a useful metric should stay a metric, not become a health grade for every food.
The useful takeaway
Lean fish, egg whites, turkey, chicken and nonfat high-protein dairy are especially efficient ways to add protein without many calories.
Legumes, nuts, seeds and fatty fish can rank lower on this one measure while contributing nutrients the ranking was never designed to capture.
Sources
- USDA FoodData Central — Protein and energy values.