20g of Protein Costs 83 Calories. Or 1,815

Twenty grams of protein costs 83 calories if you take it from cooked shrimp and 1,815 calories if you take it from raw macadamia nuts — a 22-fold spread across the same fixed target. Both figures come from USDA FoodData Central rows: shrimp at 24.0g of protein and 99 calories per 100g, macadamias at 7.91g and 718.

Per-calorie leaderboards ask which food carries the most protein per 100 calories. That question has a well-known failure — it rewards whatever is mostly water, which is why we had to print the portion sizes beside an iron ranking before it made sense. This post asks the inverted question, which is the one people actually have: you want 20g of protein, so what does it cost you? The nutrient is fixed and the calories vary.

What 20g of protein costs, cheapest first

Grams is the portion you would have to eat. Calories is the price of that portion. Every row is derived from one USDA row per food, all states as published (raw where the row says raw).

All ten of the cheapest are animal-derived, and six of them are seafood. That is not a diet recommendation, it is what happens when you divide a fixed protein target by foods that are mostly protein and water with very little fat. Cooked shrimp wins because 83g of it is a small portion that happens to be a quarter protein by weight.

Two rows in that table need a warning label

Whey protein powder is 9th at 98 calories, and it is not a food in the sense the other rows are. Its USDA description reads "Beverages, Protein powder whey based": something a company blended and packed, measured at 78.13g of protein per 100g, which is why 26g clears the target. The row documents a tub on a shelf rather than an ingredient. It belongs in the ranking because it is honestly one of the cheapest routes to 20g; it does not belong in a sentence about which whole foods are protein-dense.

Tamari soy sauce is 11th at 114 calories, and reaching 20g of protein from it means drinking 190g of soy sauce. The arithmetic is right and the row is real. It is also the clearest illustration of what a fixed-target ranking cannot see: nothing in the calculation knows that a food is a condiment. We have left it in and labelled it rather than quietly deleting it, because a reader who runs the same sum should get the same answer we did.

85 of 182 foods cannot reach 20g of protein at all

Only 97 of the 182 foods we can rank reach 20g of protein inside 500g of food. The other 85 do not reach it in any portion a person actually eats, so they are excluded from the ranking rather than listed at the bottom of it — a food that needs 1.4kg is not in 200th place, it is not playing.

The composition of those 85 is the useful part. Sixty-six of them — 33 fruits and 33 vegetables — are produce. Eight are grains, seven are dairy or egg products, two are sweets and two are nuts and seeds. If you have ever been told to get your protein from vegetables, this is the arithmetic behind why that advice needs a legume attached to it.

What it costs if you are not eating animals

Thirty-seven of the 97 are plant foods, and the cheapest real one is firm tofu at 166 calories for 116g (setting the soy sauce row aside for the reason above).

Quinoa is the best-placed grain in the entire dataset and it needs 455g cooked and 545 calories to deliver 20g of protein. That is the honest ceiling on grains as a protein source: not that they have none, but that the portion arrives with six and a half times the calories of the shrimp that does the same job. Firm tofu and edamame are the two plant foods that land in the same range as the animal foods, and both are soy.

The median is the number worth remembering

Across the 97 foods that can reach it, the median cost of 20g of protein is 293 calories in a 231g portion — cooked red kidney beans, as it happens. That is the middle of the distribution, not the top of it. Most foods that can get you to 20g charge you roughly three times what the leaders do.

Which is why the spread matters more than the winner. Moving from a median food to a top-ten food saves you around 200 calories per 20g of protein. Do that twice a day and the arithmetic is worth more than most of what gets called a diet.

What these numbers cannot tell you

Every figure here is one USDA row per food in the state that row describes. Raw where it says raw — raw yellowfin tuna is not the tuna steak you cook, and cooking changes the water and therefore both columns. We hold no cooked row for several of these foods and have not estimated one. Protein quality — amino acid profile, digestibility — is a real difference between these foods and is not in this dataset either, which matters most for the plant rows. And seven of the 189 foods we hold are excluded from all 182-food arithmetic on this site because their stored values are wrong or negative; they are not silently averaged in.

The part that is hard on a Tuesday

Knowing that shrimp costs 83 calories and quinoa costs 545 takes five minutes to read and about a week to forget. What survives contact with a normal Tuesday is whether you can keep a running total of the food already on your plate — and almost nobody can, unaided, past the second day.

That is the job Sunn does inside WhatsApp. Photograph the plate, or type "140g shrimp and a cup of lentils", and the protein and the calories land back in the thread. No app to install, no database to search, no deciding which of four tuna entries is the one in your tin.

Elsewhere on the site: every food we hold sorted by protein, the per-100-calorie protein ranking this post inverts, the protein calculator for your own target, and the full breakdowns for raw turkey breast and raw macadamia nuts — the two ends of this table.