How much protein is in 100g of tuna?

Tuna is one of the most protein-dense commonly eaten fish. A 100-gram serving is usually in the mid-20s for protein, but the range depends on the product. Fresh tuna steaks, canned tuna in water, and canned tuna in oil do not all weigh the same once drained or cooked, so the protein per 100g can shift a little.

As a practical rule, expect about 23–30 g of protein per 100 g. Canned light tuna in water is often near the middle of that range when drained, while some lean fresh tuna steaks can land around the same amount or slightly lower/higher depending on moisture loss during cooking. USDA FoodData Central is the best place to check a specific entry for the exact product you bought.

What else is in 100g of tuna?

Besides protein, tuna is usually low in carbohydrates and relatively low in fat, especially when it’s packed in water. That makes it useful if you’re trying to keep calories down while still getting a high-protein meal. Tuna also provides important nutrients such as vitamin B12, selenium, and, in some types, omega-3 fats.

If you compare tuna to other protein foods, it stands out for its protein-per-calorie ratio. That’s why it often shows up in meal plans for fat loss, muscle gain, and high-protein lunches. If you’re logging meals from a photo, Fitnit’s meal scanning can help you estimate macros faster, which is handy when you’re trying to compare tuna portions or track a full day of protein.

Is tuna a complete protein?

Yes. Tuna is a complete protein, meaning it contains all nine essential amino acids in amounts your body can use. That makes it a strong option for supporting muscle repair, recovery, and overall protein intake.

Protein quality matters when you’re building meals around a single main ingredient. Tuna can work especially well alongside carbohydrates and vegetables, such as in a rice bowl, salad, sandwich, or pasta dish. If you’re using tuna as part of a workout-focused eating plan, pairing it with resistance training is what helps translate protein intake into muscle maintenance or growth.

What to know about mercury and serving size

Tuna is nutritious, but mercury content is the main reason not to overdo it. The amount varies a lot by species: albacore generally contains more mercury than canned light tuna, and larger predatory fish tend to carry more than smaller fish. That’s why serving frequency matters, especially for pregnant people, children, and anyone who eats tuna often.

For most healthy adults, tuna can fit into a balanced diet when portions are reasonable and the type is chosen carefully. If you eat tuna regularly, vary your protein sources with salmon, sardines, eggs, Greek yogurt, chicken, beans, tofu, or lean meats to reduce repeated exposure to the same fish.

Tips

• Check whether the label says drained weight, since canned tuna can lose a lot of liquid.
• Use water-packed tuna if you want fewer calories and less added fat.
• Rotate tuna with other protein foods so your diet stays more varied.
• If mercury is a concern, choose canned light tuna more often than albacore.
• For meal tracking, log the exact tuna type and serving size instead of estimating by can size.