Tuna is one of the lowest-fat protein sources you can eat. A 3-ounce serving of cooked yellowfin tuna contains just 0.2 grams of saturated fat, and 89% of its calories come from protein. How much total fat ends up on your plate depends on the type of tuna and how it’s packed or prepared.
Fat Content by Type and Packaging
Fresh tuna steaks and water-packed canned tuna are both extremely lean. A 3-ounce serving of cooked yellowfin tuna has about 1 gram of total fat and 110 calories. Per ounce, canned tuna in water contains 0.9 grams of fat and just 24 calories.
Canned tuna packed in oil tells a different story. Per ounce, oil-packed tuna has 2.3 grams of fat and 56 calories. Scale that up to a standard 5-ounce can, and you’re looking at 280 calories versus 120 for the water-packed version. The tuna itself is still lean, but it absorbs a significant amount of the oil it sits in. If you’re choosing tuna specifically because it’s low fat, water-packed is the way to go.
How Tuna Compares to Other Lean Proteins
Tuna holds its own against the leanest proteins available. In a 3-ounce serving, yellowfin tuna delivers about 25 grams of protein for 110 calories. Skinless chicken breast, often considered the gold standard for lean protein, provides 27 grams for 140 calories. Both are excellent choices, but tuna edges ahead slightly in terms of its protein-to-calorie ratio: 89% of tuna’s calories come from protein compared to 73% for chicken breast.
Cod, another famously lean fish, matches tuna’s protein percentage (89% of calories from protein) but delivers less total protein per serving, around 16 grams in 3 ounces.
The Fat in Tuna Is Mostly the Good Kind
What little fat tuna does contain is rich in omega-3 fatty acids, the type linked to heart health and reduced inflammation. The amount varies by species. Bluefin tuna has the most, with about 1.6 grams of combined EPA and DHA (the two omega-3s your body uses most readily) per 100-gram serving. Albacore, the variety most commonly sold as “white” canned tuna, provides about 1.3 grams. Light canned tuna, typically skipjack, comes in lower at roughly 0.5 grams per 100 grams.
Even at those lower amounts, a couple of servings per week contributes meaningfully to your omega-3 intake. The saturated fat content, the type associated with cardiovascular risk, is negligible at 0.2 grams per cooked 3-ounce serving of yellowfin.
Mercury Limits Worth Knowing
Because tuna is so lean and protein-dense, it’s tempting to eat it daily. Mercury is the main reason to moderate your intake. The EPA and FDA recommend adults eat 2 to 3 servings of fish per week from lower-mercury options, or 1 serving per week from moderate-mercury options. Light canned tuna (skipjack) falls into the lower-mercury category, while albacore and yellowfin carry more mercury and should be eaten less frequently. For children, the guidance is 2 servings per week from the lower-mercury list.
Cooking Tips for a Low-Fat Fish
Tuna’s extremely low fat content makes it prone to drying out during cooking. Fresh tuna steaks stay tender when seared quickly at high heat and left pink in the center. If you prefer it cooked through, lower temperatures help retain moisture.
For canned tuna dishes like patties or casseroles, water-packed tuna benefits from a bit of added oil during cooking to prevent it from turning tough. Oil-packed tuna already has enough fat to stay moist through most preparations, which gives it a richer flavor and more forgiving texture. If you’re watching fat intake closely, starting with water-packed tuna and adding just a small amount of olive oil gives you control over exactly how much fat ends up in the dish.
Cold preparations like tuna salad sidestep the dryness problem entirely. Mixing water-packed tuna with Greek yogurt instead of mayonnaise keeps the dish high in protein and low in fat while adding creaminess.