Canned Tuna Leads Seafood Protein, Then Drops to 8th

Weigh it, and oil-packed canned tuna wins the seafood protein contest outright: 29.1g per 100g. Price the same 19 foods by what they cost you in calories and the tin drops to 8th, at 14.7g. Cooked shrimp is what tops that second list: 24.2g per 100 calories, which is 65% more protein for the same energy than the tin that beat it on the scales. Both numbers come from USDA FoodData Central (tuna is FDC 173708, shrimp FDC 175180).

The three foods at the top of the by-weight list are all canned in oil: tuna, anchovies and sardines. Per 100 calories they sit 8th, 12th and 14th. That is the whole story of this list, and it is worth a minute.

Which seafood has the most protein?

Per 100g, tuna canned in oil at 29.1g. Per 100 calories, cooked shrimp at 24.2g. Nineteen foods, two columns, two different winners. Nothing about the fish changed between them.

The same fish is 4th and 8th at the same time

Fresh yellowfin tuna gives 22.39g of protein per 100 calories. Light tuna canned in oil gives 14.70g — 34% less, from the same fish. By weight the canned one looks better: 29.1g per 100g against 24.4g.

The difference is the oil. Canned-in-oil tuna carries 8.21g of fat per 100g against fresh yellowfin's 0.49g, and fat is 9 calories a gram. That pushes the canned row to 198 calories per 100g while the fresh row sits at 109. The protein barely moved. The calories nearly doubled.

This is not an argument against canned tuna. Drained oil-packed tuna is cheap, keeps for years and needs no cooking, and 100g of it really does hand you 29.1g of protein. It is an argument against reading a per-100g table as if calories were not part of the deal.

What 36g of protein costs you

150g of cooked shrimp is 36.0g of protein and 149 calories. The same 36g of protein from oil-packed canned tuna takes 124g and 245 calories. That is 96 calories of difference for an identical protein number — close to a slice of bread, every time you make that swap.

Six foods clear 20g of protein per 100 calories: shrimp, fresh yellowfin tuna, Atlantic cod, blue crab, northern lobster and tilapia. Five of the six carry under 1g of fat per 100g. That is the pattern — the per-calorie leaders are the lean ones, and lean here means genuinely lean, not "lower in fat than salmon".

Why oily fish sits at the bottom, and why that is fine

Farmed Atlantic salmon is 15th of 19 at 9.81g of protein per 100 calories, and Atlantic mackerel is 16th at 9.07g. Both are oily fish — 13.4g of fat per 100g in the salmon row, 13.9g in the mackerel. Judged on protein per calorie alone, both look poor.

Protein per calorie is one question, not the only one. The fat in salmon and mackerel is the reason people eat them, and this table does not measure it. If you want the fat picture instead, our salmon and shrimp fat comparison takes the same two foods from the opposite end.

Two rows that are not what their names suggest

Our clam row is last at 7.03g of protein per 100 calories because it is breaded and fried, and our halibut row is second-last at 7.74g because it is Greenland halibut, which carries 13.8g of fat per 100g. Neither is a fair reading of a plain clam or a plain halibut fillet.

We say so rather than quietly dropping them. Those are the USDA rows we hold, breading and all, and a table that hid them would be tidier and less true. Typical lean halibut is a different food from the Greenland row, and a steamed clam is a different food from a fried one.

The oyster row is the other one worth flagging: 5.22g of protein per 100g is the lowest by weight on the whole list by a wide margin — the next lowest is scallops at 12.06g. Raw eastern oysters are only 59 calories per 100g, so per calorie they climb to 8.85g and 17th place, ahead of the Greenland halibut and fried clam rows but behind everything else.

Pick two and compare them properly

Every figure above has a page of its own behind it — shrimp, cod and canned tuna. If you are choosing between two of them, shrimp vs yellowfin tuna and crab vs shrimp put the rows side by side.

The tin is the hard part

Canned fish is where tracking quietly goes wrong. A drained tin is not the tin's stated weight, oil-packed and water-packed are different foods with different calorie counts, and almost nobody weighs what ends up on the plate. We hold only the oil-packed row, so the water-packed figure is not ours to quote.

Sunn is built to absorb that guess. Message it "tin of tuna in oil, drained, on toast" and you get a sensible entry back straight away — it only follows up when the answer would genuinely move your totals. Nothing to weigh, nothing to search, no app to open.