Salmon vs tuna: which fish wins on nutrition?

Salmon vs tuna is the most common matchup in the seafood aisle, and the honest answer is that neither fish wins outright. It depends on what you are optimizing for. To keep this concrete, we will compare the two forms most Americans actually buy: sockeye salmon and light tuna canned in water, drained. Both are in our index, both are scored on the same 1 to 100 nutrient density scale, and the USDA numbers behind them tell a surprisingly clean story.

The headline numbers

Per 100 grams, canned light tuna carries 86 calories, 19.4 grams of protein, and just under 1 gram of fat. Sockeye salmon carries 131 calories, 22.2 grams of protein, and 4.69 grams of fat. On our index, the tuna scores 79 and the sockeye scores 74. Both are strong scores for animal foods, which tend to sit below leafy greens on a per-calorie scale, but the gap between them is real and it comes almost entirely from fat and calories.

Protein per calorie: tuna takes it

This is the cleanest win in the whole comparison. Divide protein by calories and canned light tuna delivers about 22.6 grams of protein per 100 calories. Sockeye salmon delivers about 16.9 grams per 100 calories. That is roughly a third more protein for the same energy budget. If your plan is built around hitting a protein target inside a strict calorie ceiling, tuna is one of the most efficient whole foods in our entire database, not just in the seafood category.

Salmon is no slouch. At 22.2 grams of protein per 100 grams, sockeye actually has more protein by weight than the tuna. The difference is that salmon's fat rides along and raises the calorie count, so each gram of protein costs you more energy.

Fat profile: salmon's fat is the point

Here the framing flips. Canned light tuna is nearly fat free at 0.96 grams per 100 grams, with only 0.211 grams of that saturated. Sockeye carries 4.69 grams of fat, and still only 0.814 grams saturated. In other words, the extra fat in salmon is overwhelmingly unsaturated, and salmon is one of the classic food sources of long-chain omega-3 fats. Our density score is calorie-anchored, so it quietly penalizes salmon for that fat, but if fish fat is exactly what you came for, the lower score is not a mark against it.

Salmon also brings more of several other nutrients per 100 grams: 367 milligrams of potassium against tuna's 179, 30 milligrams of magnesium against 23, and more vitamin A. Tuna answers with more iron, 1.63 milligrams against 0.43. Neither fish has any fiber, sugar, or carbohydrate to speak of.

Sodium: the canned-food tax

• Sockeye salmon, raw: 78 milligrams of sodium per 100 grams.
• Light tuna, canned in water, drained: 247 milligrams per 100 grams.
• For contrast, smoked chinook salmon jumps to 672 milligrams, and its density score drops to 53.

Canning and curing are where fish quietly picks up salt. The tuna's 247 milligrams is manageable inside a normal day, but it is roughly three times what fresh sockeye carries, and it is the main reason a low-sodium eater should lean toward fresh fish. If you buy canned, draining helps, and no-salt-added cans close most of the gap.

What the density scores say

Canned light tuna scores 79 on our index. Sockeye salmon scores 74. Both earn the high-protein tag, and sockeye adds the low-sodium tag that the canned tuna cannot claim. The five-point spread mirrors the protein-per-calorie math: the score is a per-calorie measure, so the leaner fish edges ahead. Other salmons in our index line up just behind sockeye, with pink salmon at 70, wild Atlantic salmon at 66, and fattier farmed Atlantic salmon at 64. The pattern is consistent: more fat, more calories, lower per-calorie score.

The verdict, by goal

Cutting calories: tuna wins. At 86 calories per 100 grams it is one of the leanest protein sources you can buy, and its 79 density score reflects that efficiency. You can eat a larger, more filling portion for the same energy.

Building muscle: tuna wins on protein economics, but it is closer than it looks. Tuna gives you the most protein per calorie and per dollar. Salmon gives you slightly more protein per bite plus extra calories that a hard-training eater in a surplus may actually want. If calories are not scarce, either fish does the job.

Heart health angle, by the numbers: sockeye salmon is the pick. It carries the unsaturated fat that makes fatty fish famous, roughly a third of the sodium of the canned tuna, and about twice the potassium. Those are simply the nutrient facts, and they all point the same direction.

The best move is not choosing one forever. It is knowing which fish matches the day. And you do not have to take our word for the numbers: open both foods in our compare tool, put sockeye salmon and canned light tuna side by side, and the trade-off is visible in about five seconds.