A standard 5-ounce can of tuna packed in water contains about 120 calories, making it one of the leanest protein sources available. That same size can packed in oil jumps to around 280 calories. Beyond canned tuna, the calorie count varies significantly depending on the species, the cut, and how you prepare it.
Canned Tuna: Water vs. Oil
The packing liquid is the single biggest factor in canned tuna calories. A 5-ounce can of chunk light tuna in water has roughly 120 calories, while the same can in oil has about 280 calories. That’s more than double, and most of the extra calories come from fat absorbed into the fish during packing.
Draining oil-packed tuna helps, but it doesn’t eliminate the difference. Even after draining, oil-packed tuna retains around 200 calories per can because the fish absorbs a portion of the oil. If you’re counting calories closely, water-packed tuna is the clearer choice. Draining water-packed tuna, on the other hand, barely changes the calorie count since the fish doesn’t absorb significant calories from water.
Calories by Tuna Species
Not all tuna is created equal. Fat content varies dramatically between species, and fat is the main driver of calorie differences. Here’s how the most common varieties compare per 3.5-ounce (100-gram) cooked serving:
- Yellowfin (ahi): 130 calories, 0.59 g fat. This is the leanest fresh tuna you’ll find, and it’s the variety most often sold as seared ahi steaks.
- Canned light tuna (skipjack): Around 120 calories per 5-ounce can in water. Skipjack is the most common species in “chunk light” cans and is comparable to yellowfin in leanness.
- Canned white albacore in water: 128 calories, 2.97 g fat per 3.5 ounces. Slightly fattier than light tuna, with a milder, firmer texture.
- Bluefin (cooked): 184 calories, 6.28 g fat per 3.5 ounces. The fattiest common tuna species by a wide margin, prized in sushi restaurants for its rich flavor.
The general rule: the fattier the species, the higher the calorie count. Among fresh tuna, the ranking from leanest to fattiest goes yellowfin, skipjack, albacore, and then bluefin at the top.
Bluefin Cuts: Lean vs. Fatty
If you eat sushi or sashimi, the cut of bluefin matters enormously. The lean red meat (akami) and the fatty belly (toro) come from the same fish but have very different nutritional profiles. Toro, especially o-toro from the fattiest part of the belly, contains dramatically more fat than akami. The protein content in toro is also lower than in leaner cuts, meaning a higher percentage of its calories come from fat.
Chu-toro, the medium-fatty belly cut, falls in between. For context, a piece of o-toro can contain several times more fat than the same weight of akami. This is why toro tastes buttery and rich while akami has a clean, meaty flavor. If you’re watching calories at a sushi restaurant, akami and other lean nigiri will keep you closer to that 130-calorie-per-3.5-ounce range, while toro pushes well above it.
Why Tuna Is a Protein Standout
Tuna’s reputation as a fitness food comes down to its protein density. Most of the calories in lean tuna varieties come from protein rather than fat or carbohydrates. A can of light tuna in water delivers roughly 26 grams of protein for just 120 calories, with virtually no carbs. That protein-to-calorie ratio is hard to beat, even compared to chicken breast.
Tuna also provides meaningful amounts of selenium and vitamin B12. Selenium supports thyroid function and acts as an antioxidant, while B12 is essential for nerve function and red blood cell production. A single serving of tuna can cover a substantial portion of your daily needs for both nutrients.
Mercury and How Much to Eat
Mercury is the main health consideration with tuna, and the amount varies by type. Canned light tuna (typically skipjack) falls in the FDA’s “Best Choices” category, meaning 2 to 3 servings per week is considered safe. White albacore tuna contains roughly three times more mercury than light tuna and falls in the “Good Choices” category. The FDA recommends limiting albacore to 1 serving per week, with no other fish that week.
Larger species like bluefin and bigeye accumulate more mercury because they’re higher on the food chain and live longer. If you eat fresh tuna steaks or sushi-grade tuna regularly, it’s worth paying attention to which species you’re choosing and rotating with lower-mercury fish.
Keeping Calories Low When Preparing Tuna
The simplest way to keep tuna low-calorie is to start with water-packed cans and use lighter mix-ins. A can of tuna in water mixed with a tablespoon of mayonnaise adds roughly 90 calories from the mayo alone, nearly doubling the total. Greek yogurt, mustard, or a squeeze of lemon juice are common swaps that keep the calorie count closer to the tuna itself.
For fresh tuna steaks, cooking method matters less than what you cook with. A seared ahi steak brushed with a teaspoon of oil adds about 40 calories from the oil. Grilling or baking with minimal added fat keeps a 4-ounce yellowfin steak under 160 calories total. Bluefin needs less added fat because its natural oils keep it moist during cooking.