DIAAS: The Simple Way to Check Protein Quality

Ever wonder why some protein powders claim to be better than others? The answer often lies in a score called DIAAS. It stands for Digestible Indispensable Amino Acid Score and it tells you how much of each essential amino acid your body can actually use from a food.

How DIAAS Is Measured

DIAAS looks at the digestibility of each essential amino acid (the ones you can’t make yourself). Scientists feed a small amount of the food to test animals, measure how much of each amino acid shows up in the bloodstream, and compare that to a reference pattern for humans. The lowest ratio among the amino acids becomes the food’s DIAAS. A score of 100 or more means the protein provides all the amino acids you need in the right amounts.

Unlike the older PDCAAS method, DIAAS doesn’t cap the score at 100 and it accounts for where in the gut the protein is digested. This makes the number more realistic for real‑world eating.

Using DIAAS to Choose Better Foods

When you’re picking protein sources, look for a DIAAS of 75 or higher for most adults. Eggs, whey, soy, and most animal meats usually hit that mark. Some plant proteins, like pea or lentil, can be lower, but combining them can raise the overall score.

Here’s a quick cheat sheet:

  • Eggs – DIAAS ≈ 100
  • Whey – DIAAS ≈ 104
  • Beef – DIAAS ≈ 92
  • Soy – DIAAS ≈ 73
  • Pea – DIAAS ≈ 66
If you’re vegetarian or vegan, pair a legume with a grain (like beans + rice) to push the combined DIAAS above 75.

Another tip: pay attention to cooking. Over‑cooking can lower digestibility, dropping the DIAAS a bit. Light steaming or quick sautéing usually keeps the numbers high.

So next time you shop, glance at the protein source and think about its DIAAS. Picking higher‑scoring foods helps you meet your muscle‑building, recovery, or overall health goals without needing extra supplements.

Remember, DIAAS is just one tool. It doesn’t replace a balanced diet or personal needs, but it gives a clear, science‑based way to compare protein quality. Use it alongside calories, fiber, and micronutrients, and you’ll have a solid picture of what’s really feeding your body.