Tuna is one of the best protein sources available, packing around 42 grams of protein in a single can (165g) of light tuna in water, with only 191 calories. That protein-to-calorie ratio makes it a top choice for anyone looking to build muscle, lose weight, or simply hit their daily protein goals without excess fat or calories.
How Tuna Stacks Up Against Other Proteins
Per 100 grams, cooked yellowfin tuna delivers about 29 grams of protein with less than 1 gram of fat. Roasted chicken (with skin) provides 27 grams of protein per 100 grams but comes with 13.6 grams of fat. That’s a massive difference in fat content for a very similar protein yield. If you’re comparing skinless chicken breast specifically, the protein numbers are closer, but tuna still edges it out while being one of the leanest protein sources you can eat.
Beyond the raw numbers, tuna’s protein is high quality. Fish products score between 0.9 and 1.0 on the standard scale used to measure protein quality (where 1.0 is the highest possible score). Tuna contains all the essential amino acids your body can’t make on its own, including lysine, methionine, threonine, and tryptophan. This means the protein you get from tuna is efficiently used for muscle repair, immune function, and other processes that depend on a complete amino acid supply.
Canned vs. Fresh: Does It Matter?
Canned tuna is the most convenient and affordable way most people eat tuna, and the protein holds up well through the canning process. That said, cooking and processing do affect how much protein your body actually absorbs. Lab studies measuring digestive efficiency found that raw tuna had about 81% protein bioaccessibility, while boiled and grilled tuna came in at 73% and 72%, respectively. Canned tuna falls in a similar range to cooked tuna.
In practical terms, this difference is small enough that it shouldn’t change your habits. A can of tuna still delivers far more usable protein per dollar than most alternatives. The main trade-off with canning is texture and flavor, not nutrition. If you prefer canned tuna packed in water over oil, you’ll also keep the calorie count lower while preserving nearly all the protein content.
What Else You Get Beyond Protein
Tuna isn’t just a protein vehicle. A 3-ounce serving of canned light tuna in water provides about 0.19 grams of omega-3 fatty acids. That’s a modest amount compared to fattier fish like salmon or mackerel, but it still contributes to your weekly intake of these fats, which support heart and brain health. The American Heart Association recommends eating two servings of fish per week, with a serving defined as 3 ounces cooked (roughly three-quarters of a cup of flaked fish). Bluefin tuna specifically is listed among the fatty fish highest in omega-3s, while canned light tuna is leaner.
Tuna is also rich in selenium, a mineral that plays a role in thyroid function and acts as an antioxidant. For people who struggle to get enough variety in their diet, adding tuna a couple times a week covers multiple nutritional bases at once.
How Much Tuna You Can Safely Eat
Mercury is the one real concern with tuna, and the answer depends on the type you’re eating. The EPA and FDA categorize canned light tuna as a “Best Choice,” meaning you can safely eat two to three servings per week. Albacore (white) tuna contains more mercury and falls into the “Good Choice” category, with a recommended limit of one serving per week.
For children, the guidance is more conservative: two servings per week from the “Best Choices” list, which includes canned light tuna. If you’re rotating between different types of fish throughout the week, you have plenty of room to include tuna regularly without approaching mercury levels that would be a concern.
The practical takeaway is that two to three cans of light tuna per week fits comfortably within safety guidelines for most adults. If you prefer albacore for its milder taste and firmer texture, just keep it to one serving weekly and fill the rest of your fish intake with lower-mercury options.
Easy Ways to Use Tuna for High-Protein Meals
A single can of tuna in water gives you roughly 42 grams of protein for under 200 calories. That’s nearly half the daily protein target for a 150-pound adult, from one inexpensive ingredient. Mixed into a salad, it creates a meal with minimal prep. Tossed with pasta, vegetables, and a light dressing, it becomes a full dinner. Spread on whole-grain toast, it works as a quick post-workout snack.
For meal prep, canned tuna is hard to beat. It’s shelf-stable, requires no cooking, and mixes well with a wide range of flavors. If the typical mayo-heavy tuna salad doesn’t appeal to you, try mixing it with Greek yogurt, mustard, and chopped celery for a lighter version that adds even more protein. Or combine it with white beans, lemon juice, and olive oil for a Mediterranean-style protein bowl that covers your healthy fats and fiber in one sitting.