Which is cheaper for protein, canned tuna (in water) or oats (dry)?

Oats (dry), at $0.009 per gram of protein against $0.042 for canned tuna (in water) (July 2026 US grocery prices). A 30 g protein serving costs $0.27 vs $1.27.

Which has more protein per calorie, canned tuna (in water) or oats (dry)?

Canned tuna (in water), with 22.4 g protein per 100 kcal against 4.3 g for oats (dry), 5.2x leaner. That matters when you are cutting and calories are the binding constraint.

Which should I buy, canned tuna (in water) or oats (dry)?

Depends on your constraint. On a tight budget with room in your calories, oats (dry) is cheaper per gram of protein. On a calorie-capped cut, canned tuna (in water) gives you 5.2x more protein per calorie and is usually worth its $0.042/g price.

Protein head-to-heads · July 2026

Canned tuna (in water) vs Oats (dry): which protein is cheaper?

USDA macros joined to current US grocery prices, reduced to the two numbers that decide it: dollars per gram of protein, and protein per calorie.

Oats (dry) is 4.8x cheaper per gram of protein ($0.009/g vs $0.042/g), while Canned tuna (in water) is the leaner choice at 22.4 g protein per 100 kcal against 4.3 g. Budget favours one, a calorie cap favours the other.

Food	$/g protein	30 g protein costs	You need	kcal that come with it	Protein/100 kcal
Canned tuna (in water)	$0.042	$1.27	115 g	134 kcal	22.4 g
Oats (dry)	$0.009	$0.27	178 g	691 kcal	4.3 g

Full macros, per serving

Food (per serving)	Price	kcal	Protein	Carbs	Fat
Canned tuna (in water) (100 g)	$1.10	116	26 g	0 g	1 g
Oats (dry) (100 g)	$0.15	389	16.9 g	66 g	6.9 g

A week of protein from each

Hitting a common 100 g/day protein target from oats (dry) alone costs $6.21 a week; from canned tuna (in water) alone, $29.62. That is a gap of $23.40 every week for the same protein. In practice you mix sources: the planner computes the cheapest mix for your exact target and calorie cap, live from the same dataset.

Budget says one, calories say the other

Oats (dry) costs $0.009 per gram of protein against $0.042, so it saves $23.40 a week at a 100 g/day target. Canned tuna (in water) answers a different question: 22.4 g of protein per 100 kcal against 4.3 g, which is what matters once calories, not dollars, are the thing you run out of first.

What the calories cost you

Getting 30 g of protein from oats (dry) brings 691 kcal with it. On a 2,000 kcal day, three servings would be most of your budget before anything else goes on the plate. That is fine when you are eating at maintenance or building, and it is the reason this food falls apart on a cut no matter how good the price per gram looks.

The gap here is 4.8x, which is unusual

Most matchups in this dataset land inside 2x. Canned tuna (in water) costing 4.8x what oats (dry) does for the same gram of protein means you are buying something other than protein: processing, shelf stability, convenience or flavour. Worth paying for sometimes, but name it, because at a 100 g/day target that gap is $23.40 a week and $1216.92 a year.

On a cut these are not comparable

Canned tuna (in water) carries 5.2x the protein per calorie that oats (dry) does. When you are eating at a deficit, that ratio is the whole game: the same 30 g of protein arrives with 134 kcal from one and 691 kcal from the other. The cheaper option stops being cheaper once you count what you had to give up elsewhere to fit it in.

Compare against other foods

Frequently asked

Which is cheaper for protein, canned tuna (in water) or oats (dry)?: Oats (dry), at $0.009 per gram of protein against $0.042 for canned tuna (in water) (July 2026 US grocery prices). A 30 g protein serving costs $0.27 vs $1.27.
Which has more protein per calorie, canned tuna (in water) or oats (dry)?: Canned tuna (in water), with 22.4 g protein per 100 kcal against 4.3 g for oats (dry), 5.2x leaner. That matters when you are cutting and calories are the binding constraint.
Which should I buy, canned tuna (in water) or oats (dry)?: Depends on your constraint. On a tight budget with room in your calories, oats (dry) is cheaper per gram of protein. On a calorie-capped cut, canned tuna (in water) gives you 5.2x more protein per calorie and is usually worth its $0.042/g price.

Prices are representative US grocery prices as of July 2026; your store will differ. Educational content, not medical or dietary advice. Dataset: free download, CC-BY.