Dried pinto beans still bought the most usable protein per dollar in our sample, about 58 grams, even after we docked every food for protein quality. That’s the headline, and it surprised me, because this whole exercise was built to test the complaint we get most: beans aren’t a complete protein, so ranking them first is cheating. We checked. Beans held the top spot, just by a lot less than before.
A few weeks ago I ranked 49 grocery foods by protein per dollar and dried beans ran away with it. The pushback was fair. A gram of protein from beans isn’t the same as a gram from eggs, because your body can’t use all of it. So I took the audited numbers from that study, multiplied each by a published quality score, and rebuilt the ranking. Same prices, same grams, now weighted for what your body actually absorbs.
What is DIAAS, in plain English?
DIAAS stands for Digestible Indispensable Amino Acid Score, the current standard for grading protein quality. It answers two things at once: does a food carry the essential amino acids in the amounts your body needs, and how much of that protein do you actually absorb. A score of 1.0 means the protein covers your needs on its own. A score of 0.5 means the food is short somewhere, so half of that protein doesn’t pull its weight. Eggs and dairy sit above 1.0. Most beans and grains land between 0.4 and 0.65. That spread is the whole story.
How we ran the quality adjustment
The base numbers didn’t change. Protein per dollar is pulled verbatim from the original study. Each food’s DIAAS is a published value, capped at 1.0 for the math so nothing scores a quality bonus above its raw grams. Quality-adjusted protein per dollar is just the two multiplied together, an estimate of usable protein per dollar.
Every DIAAS value carries a named source, drawn from peer-reviewed work (Nosworthy on cooked pulses, the Phillips 2017 review, Herreman 2020, Rutherfurd 2015, Mathai 2017, Burd 2019) and the FAO 2013 report. The full quality-adjusted CSV is public, one row per food with the score and its citation. One caveat: DIAAS values shift between studies depending on the reference pattern and cooking method, so read these as solid estimates, not lab constants for your exact groceries.
Does the ranking flip when you adjust for quality?
Parts of it flip hard. The top doesn’t.
| Rank | Food | Raw g per $1 | DIAAS | Adjusted g per $1 |
|---|---|---|---|---|
| 1 | Pinto beans (dry) | 97.9 | 0.59 | 57.8 |
| 2 | Chicken drumsticks (bone-in) | 50.3 | 1.08 | 50.3 |
| 3 | Brown lentils (dry) | 77.7 | 0.63 | 49.0 |
| 4 | Black beans (dry) | 81.0 | 0.59 | 47.8 |
| 5 | Chickpeas (dry) | 56.7 | 0.83 | 47.1 |
| 6 | Navy beans (dry) | 75.9 | 0.57 | 43.3 |
| 7 | Whole wheat flour | 96.0 | 0.45 | 43.2 |
| 8 | Green split peas (dry) | 73.9 | 0.58 | 42.9 |
| 9 | Red lentils (dry) | 56.0 | 0.63 | 35.3 |
| 10 | Eggs (large) | 34.4 | 1.13 | 34.4 |
| 11 | Mozzarella (part-skim) | 30.1 | 1.14 | 30.1 |
| 12 | Whole milk | 29.1 | 1.14 | 29.1 |
| 13 | White rice (dry) | 48.0 | 0.60 | 28.8 |
| 14 | Chicken thighs (boneless) | 27.7 | 1.08 | 27.7 |
| 15 | Greek yogurt (nonfat) | 27.5 | 1.14 | 27.5 |
| 16 | Cottage cheese (4%) | 26.3 | 1.14 | 26.3 |
| 17 | Old-fashioned rolled oats | 46.6 | 0.54 | 25.2 |
| 18 | Chicken breast (boneless) | 24.5 | 1.08 | 24.5 |
| 19 | Whole wheat spaghetti | 53.4 | 0.45 | 24.0 |
| 20 | Canned tuna (in water) | 22.4 | 1.00 | 22.4 |
| 21 | Peanut butter | 50.7 | 0.43 | 21.8 |
| 22 | TVP (soy) | 22.5 | 0.90 | 20.2 |
| 23 | 100% whole wheat bread | 35.8 | 0.45 | 16.1 |
| 24 | Tofu (extra firm) | 13.6 | 0.90 | 12.2 |
| 25 | Ground beef (80/20) | 11.5 | 1.11 | 11.5 |
DIAAS above 1.0 is shown for reference. It was capped at 1.0 in the math, so eggs and dairy keep their full raw value and nothing scores a quality bonus.
Why the grains fell and the animal proteins climbed
Chicken drumsticks were the big winner, jumping from eleventh on the raw list to second. Their DIAAS is around 1.08 while legumes lose a third or more of their raw value. At roughly a dollar a pound in the bag, drumsticks quietly became the best animal-protein deal in the store once quality entered the math.
The cereal grains took the worst beating. Whole wheat flour was a near-tie for first on raw protein per dollar. Adjusted, it slid to seventh. Whole wheat spaghetti dropped about ten spots and whole wheat bread fell nine, because grains are limited by lysine. Peanut butter fell hardest of all, eleven spots, since its DIAAS sits near 0.43.
Eggs and dairy climbed without moving an inch. They didn’t get cheaper. Everything around them got discounted while they kept full value, so eggs rose five spots, and mozzarella, milk, yogurt, and cottage cheese drifted up the same way. If you want quality without cooking, that corner of the fridge is where it lives.
Do beans still win if they aren’t complete protein?
They do here, and this is the part that answers the critique. Beans are short on the sulfur amino acids, methionine and cysteine. Grains have those in surplus and are short on lysine, which beans carry in plenty. Put them together and the holes fill in. A cooked rice-and-bean plate lands around a DIAAS of 0.78, well up from either food alone, and it costs almost nothing. That’s not a lab trick. It’s why beans and rice is a staple on nearly every continent, and our cheapest complete protein pairs piece runs the same idea across other combinations.
So the complaint is real, and it still doesn’t knock beans off the top. It just means you shouldn’t build a menu out of one bag.
How to actually shop this
You don’t need a spreadsheet at the register.
- Keep beans and lentils as the cheap baseline. They still top the adjusted list, and a grain on the side handles the quality question. A batch of easy black bean tacos or a pot of lentil curry does the work.
- Make drumsticks or a whole bird your default meat. They buy more usable protein per dollar than breast, thighs, or any ground meat here.
- Let eggs and dairy do the no-cook lifting. A plate of rice and beans with an egg on top is cheap, fast, and covers the amino acid gap in one move.
- Don’t overpay for the middle. Peanut butter, whole wheat bread, and ground beef buy less usable protein than the shelf numbers suggest.
The one-sentence version is nearly the same as last time, asterisk earned honestly: the dry goods aisle still wins even after you weight for quality, beans and rice close the gap the critics point to, and the humble drumstick is the meat counter’s quiet bargain. Want the shopping system instead of another table? The high-protein budget guide turns all of this into a cart.
