Protein daily value vs grams: why a 28g protein bar can show only 40% DV

Protein label facts

Protein daily value vs grams: what's the difference?

Grams answer one question: how much protein is in this serving? They're measured the same way whatever the protein source, and under US Nutrition Facts rules they're always on the label, rounded to the nearest gram.

The % Daily Value answers a different one: how much of a 50g daily reference does this serving cover, after adjusting for protein quality? The adjustment uses a score called PDCAAS. The score is capped at 1.0, so the adjusted figure can never be higher than the grams. As the explainer at nutritionfactlabel.com puts it, "The percentage can be lower than grams divided by 50, but never higher." So grams divided by 50 is the most the %DV can be, not the floor. The %DV is also printed as a whole percent, so you can't work backward to an exact figure.

Why does a 28g protein bar show only 40% DV?

This exact question has been going around protein bar forums this fall, after a newly launched bar with 28g of protein turned out to list 40% DV. Here's the math. At full quality, 28g divided by 50g would be 56% DV. The label says 40%, and 40% of 50g is 20g. So the label is counting about 20g of the 28g as protein at full quality value.

Why the gap? The protein mix scores below 1.0 on the quality scale. When a protein is missing an essential amino acid, or is low in one, the score for the whole protein drops. People discussing that bar pointed to collagen high in its ingredient list, which we cover below.

Both numbers on that label are accurate. They answer different questions.

What is PDCAAS, in plain words?

PDCAAS stands for protein digestibility-corrected amino acid score. A 2022 review of protein quality metrics in the journal Nutrients describes how it works: the method compares a protein's digestible essential amino acids with a reference pattern, and the score of the first limiting amino acid, the one that falls shortest, becomes the score for the protein. Values are truncated at 1, or 100%.

On a US label, that score is the multiplier. Grams times the score gives the corrected amount, and the corrected amount divided by 50g gives the %DV. nutritionfactlabel.com walks through an example it calls illustrative: two products with 10g of protein each, one with a score of 1.00 and one with 0.50, print 20% DV and 10% DV.

Why is there no percent daily value for protein on most labels?

In the US, the protein %DV is optional on foods for the general public. It has to appear when the package makes a protein claim, such as "high protein," and on foods made for children under 4, according to nutritionfactlabel.com's walkthrough of the rules. A "high protein" claim needs 20% DV or more, measured with the corrected figure.

Canada leaves it off entirely. Health Canada says there is no % Daily Value for protein in its Nutrition Facts table "because most people get enough protein."

So a blank %DV cell isn't a red flag on its own. The grams are still listed.

Is collagen counted in the protein number?

Yes, in the grams. But under PDCAAS, collagen protein lacks one essential amino acid, tryptophan, as a 2019 paper in Nutrients notes, so it adds little or nothing to the quality-adjusted %DV. A bar with collagen high in its ingredient list can show a big gram number and a smaller %DV.

There's a floor, too. Under US label rules, a food for adults and children 4 and older whose protein scores below 0.20 must print either the %DV or the words "not a significant source of protein" next to the grams.

How do you read the protein line in 10 seconds?

1. Check the serving size first. Every number on the panel is per serving.
2. Read the grams. That's all the protein in the serving.
3. If a %DV is printed, multiply it by 50g. That's roughly how much of the protein counts at full quality value.
4. Glance at the ingredient list to see which protein ingredients come first.

For what counts as high protein on a label, see our guide to sustained energy bars. For what's in a protein bar, start with our ingredient guide.

Our recommendation: STAT Energy Bar

STAT Energy Bar: 100 mg caffeine, 16-19 g protein, 0 g added sugar.

If you want a bar that puts both numbers on the panel, our pick is STAT Energy Bar. Every flavor lists protein in grams and as a % Daily Value: Chocolate 16g (28% DV), Peanut Butter Espresso 17g (31% DV) and Salted Caramel Coffee 19g (34% DV). The protein blend is whey protein concentrate, milk protein isolate and whey protein isolate, plus soy protein crisps. Each bar also has 100mg of caffeine and 0g added sugar (not a low calorie food). See what's inside every STAT bar, or shop all three flavors.

What is STAT Energy Bar made for?

We've all been there: it's hour ten of a twelve, day or night, the coffee went cold an hour ago, and the next page could come any second. It might be a nurse, a resident, a first responder, or anyone pulling a long shift. That's the moment STAT Energy Bar was made for, when seconds count. Each bar has 100mg of caffeine for energy, power and alertness, about what's in a strong cup of coffee, plus 16 to 19g of protein and 0g added sugar (not a low calorie food). It's caffeine and protein you can eat in two minutes, then get right back to work. Most protein bars have no caffeine at all, but STAT has 100mg, along with maca, ashwagandha, cordyceps and reishi across the three flavors. If you like chocolate, the Chocolate bar uses coffee fruit extract. If you're a coffee person, Peanut Butter Espresso and Salted Caramel Coffee use real coffee plus coffee fruit extract. Keep a few in your bag for the shifts you can't stop for a meal, read more about our caffeinated protein bars, or shop STAT.

If you like to rotate flavors, pick up the Variety, 3 Boxes bundle, or shop all three flavors.

Protein daily value vs grams FAQ

Why does a bar with 28g of protein only show 40% DV?

The % Daily Value counts protein after adjusting for quality. 40% of the 50g Daily Value is 20g, so the label is counting about 20g of the 28g at full quality value. Grams list all the protein; %DV adjusts it.

What does protein daily value mean?

It's the share of a 50g daily reference that one serving covers, after the protein is adjusted for quality using a score called PDCAAS.

Protein daily value vs grams: which number should I read?

Read both. Grams tell you how much protein is in the serving. If a %DV is printed, it tells you how much of that protein counts at full quality value against 50g.

Why is there no percent daily value for protein?

On most US labels the protein %DV is optional, and it has to appear only when the package makes a protein claim or the food is for children under 4. Canada leaves it off entirely because, as Health Canada puts it, most people get enough protein.

What is the daily value for protein?

50 grams a day for adults and children 4 and older.

Is collagen counted in the protein number?

Collagen counts in the grams. It lacks the essential amino acid tryptophan, so it adds little or nothing to the quality-adjusted %DV.

Why do two products with the same grams of protein show different percentages?

Because the %DV uses grams multiplied by a protein-quality score, capped at 1.0. Two bars with 20g each can print different percentages if their protein sources score differently.

What is PDCAAS?

The protein digestibility-corrected amino acid score. It rates a protein by its first limiting essential amino acid, corrected for digestibility, with a top score of 1.0.

Does STAT list a % Daily Value for protein?

Yes. Chocolate has 16g of protein (28% DV), Peanut Butter Espresso 17g (31% DV) and Salted Caramel Coffee 19g (34% DV). Each bar also has 100mg of caffeine and 0g added sugar. Not a low calorie food.

Grams tell you how much; the % Daily Value tells you how much counts. If you want a bar that prints both, try STAT Energy Bar or shop all three flavors.

References

• nutritionfactlabel.com. Daily Value of Protein: Why Protein %DV Is Optional. September 19, 2026. nutritionfactlabel.com
• Health Canada. Protein. canada.ca
• Adhikari S, Schop M, de Boer IJM, Huppertz T. Protein Quality in Perspective: A Review of Protein Quality Metrics and Their Applications. Nutrients, 2022;14(5):947. pmc.ncbi.nlm.nih.gov
• Paul C, Leser S, Oesser S. Significant Amounts of Functional Collagen Peptides Can Be Incorporated in the Diet While Maintaining Indispensable Amino Acid Balance. Nutrients, 2019;11(5):1079. pmc.ncbi.nlm.nih.gov
• STAT Nutrition Facts panels and ingredient lists. statbar.com/stat-by-the-numbers