What are the macros in tuna?

Tuna is prized for its protein density. In general, plain tuna contains about 20 to 26 grams of protein per 100 grams, with very little carbohydrate and only a small amount of fat if it’s canned in water or served as a lean fresh cut. The exact tuna macro depends on the species and product form, but most plain tuna is essentially a high-protein, near-zero-carb food.

For a typical serving of canned tuna in water, drained, you’re often looking at roughly 120 to 170 calories, 25 to 36 grams of protein, and less than 2 grams of fat, depending on the can size and brand. Fresh tuna steaks are similarly protein-heavy, with calories varying more because of species and cut. If you’re tracking macros closely, always use the label or database entry that matches the exact form you ate.

Canned tuna vs. fresh tuna: why the numbers change

Canned tuna in water is usually the leanest and easiest option to log. Once drained, it tends to deliver a lot of protein for relatively few calories. Canned tuna in oil is different: some of the oil stays with the fish, which raises calories and fat, sometimes substantially. If you do not drain it well, the macro profile can shift more than you expect.

Fresh tuna, such as yellowfin or ahi, is often slightly higher in fat than water-packed canned tuna, but still lean compared with many meats. Cooked tuna also weighs less than raw tuna because it loses water during cooking, so 4 ounces raw and 4 ounces cooked are not the same serving in macro terms. For accurate tracking, measure the food the same way every time—raw, cooked, or drained—and stick with one method.

How tuna fits common macro goals

For high-protein diets, tuna is a strong choice because it gives you a large protein dose for a modest calorie count. That makes it useful for muscle maintenance during fat loss, post-workout meals, and simple lunches when you want protein without a lot of carbs. If you are trying to build muscle, tuna can help you hit your daily protein target, but it should be part of a broader diet that also provides enough total calories, carbs, and fats.

For low-carb eating, tuna is easy to work into meals because plain tuna has essentially no carbohydrate. The main macro changes usually come from what you add: mayo, bread, rice, pasta, crackers, or salad dressing can quickly change the meal’s totals. If you want a more accurate log, track the tuna separately from the mix-ins.

Health considerations when eating tuna often

Tuna is nutritious, but it is not a free-for-all food. Bigger tuna species can contain more mercury, so intake matters, especially for pregnant people, young children, and anyone eating tuna frequently. Lower-mercury choices and variety across seafood types are smart habits. The FDA and other public health agencies recommend paying attention to mercury guidance when choosing fish.

Sodium can also be a factor, especially in some canned products. Lightly salted or unsalted versions are better if you want to keep sodium lower. In other words, the best tuna macro for your goals is not just about protein and calories—it’s also about the whole nutrition picture, including mercury, sodium, and what you eat with it.

Tips

• Check whether your tuna is packed in water or oil before logging it.
• Log tuna by the form you ate it: drained canned tuna, raw steak, or cooked weight.
• Use the nutrition label for brand-specific canned tuna, since sodium and calories can vary.
• Keep mix-ins separate in your food log so mayo, rice, or bread don’t get counted as tuna.
• If you eat tuna often, rotate in other protein sources to reduce mercury exposure.