Which is cheaper for protein, canned tuna (in water) or lentils (cooked)?

Lentils (cooked), at $0.022 per gram of protein against $0.042 for canned tuna (in water) (July 2026 US grocery prices). A 30 g protein serving costs $0.67 vs $1.27.

Which has more protein per calorie, canned tuna (in water) or lentils (cooked)?

Canned tuna (in water), with 22.4 g protein per 100 kcal against 7.8 g for lentils (cooked), 2.9x leaner. That matters when you are cutting and calories are the binding constraint.

Which should I buy, canned tuna (in water) or lentils (cooked)?

Depends on your constraint. On a tight budget with room in your calories, lentils (cooked) is cheaper per gram of protein. On a calorie-capped cut, canned tuna (in water) gives you 2.9x more protein per calorie and is usually worth its $0.042/g price.

Protein head-to-heads · July 2026

Canned tuna (in water) vs Lentils (cooked): 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.

Lentils (cooked) is 1.9x cheaper per gram of protein ($0.022/g vs $0.042/g), while Canned tuna (in water) is the leaner choice at 22.4 g protein per 100 kcal against 7.8 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
Lentils (cooked)	$0.022	$0.67	333 g	387 kcal	7.8 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
Lentils (cooked) (100 g)	$0.20	116	9 g	20 g	0.4 g

A week of protein from each

Hitting a common 100 g/day protein target from lentils (cooked) alone costs $15.56 a week; from canned tuna (in water) alone, $29.62. That is a gap of $14.06 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

Lentils (cooked) costs $0.022 per gram of protein against $0.042, so it saves $14.06 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 7.8 g, which is what matters once calories, not dollars, are the thing you run out of first.

The amount you actually have to eat

Thirty grams of protein means 333 g of lentils (cooked), against 115 g for canned tuna (in water). That is a real constraint, not a footnote: a price per gram only counts if the serving is one a person will finish. Treat lentils (cooked) as the base of a meal that other protein is added to, not as the protein itself.

On a cut these are not comparable

Canned tuna (in water) carries 2.9x the protein per calorie that lentils (cooked) 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 387 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 lentils (cooked)?: Lentils (cooked), at $0.022 per gram of protein against $0.042 for canned tuna (in water) (July 2026 US grocery prices). A 30 g protein serving costs $0.67 vs $1.27.
Which has more protein per calorie, canned tuna (in water) or lentils (cooked)?: Canned tuna (in water), with 22.4 g protein per 100 kcal against 7.8 g for lentils (cooked), 2.9x leaner. That matters when you are cutting and calories are the binding constraint.
Which should I buy, canned tuna (in water) or lentils (cooked)?: Depends on your constraint. On a tight budget with room in your calories, lentils (cooked) is cheaper per gram of protein. On a calorie-capped cut, canned tuna (in water) gives you 2.9x 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.