Whey vs Greek Yogurt: 7.9× Protein, or 1.5×?

Whey protein powder has 7.9× the protein of plain lowfat Greek yogurt per 100g, and only 1.5× as much per calorie. Whey protein powder carries 78.13g of protein per 100g against plain lowfat Greek yogurt's 9.95g (USDA FoodData Central, FDC 173180 and FDC 170903). Price both per 100 calories instead and the gap collapses to 20.5g against 13.6g.

That is the number worth carrying around, because almost nobody is rationing grams of food — they are rationing calories. Getting 20g of protein costs you 98 calories as whey powder and 147 calories as Greek yogurt: a difference of 49 calories, not a difference of category.

The two rankings, side by side

Whey protein powder (dry, USDA FDC 173180) against plain lowfat Greek yogurt (FDC 170903), per 100g and per 100 calories. The right-hand column is always whey divided by yogurt, so every figure above 1 favours the powder — including the calories row, where it is a cost rather than a benefit. The last row is the one that answers the actual question.

The two right-hand columns are the same fact stated twice. Whey is a dried, concentrated food and Greek yogurt is not: protein, carbohydrate and fat together account for 15.8g of every 100g of the yogurt against 93.8g of the powder, and the remainder is mostly water. Per-100g comparisons between them are largely measuring how much water was removed. Drying a food multiplies every nutrient in it, and it multiplies the calories at the same time.

Two nutrients where Greek yogurt actually wins

Per 100 calories, Greek yogurt beats whey powder on both calcium and potassium — and on both, whey wins per 100g. These are true reversals, not narrowings, and they are the reason the basis you pick is not a technicality.

Sodium is the one that does not reverse, and it is worth noticing in the other direction: whey powder carries 2.6× the sodium per calorie. At 469mg per 100g it is a salted, formulated product, which is also a clue about what else is in it.

About that 141× iron gap

Whey powder shows 5.63mg of iron per 100g against Greek yogurt's 0.04mg — a 140.75× gap, which narrows to 27× per 100 calories. It is the largest gap between these two foods in the entire dataset, and we are not making it the headline, because it is probably not a fact about whey.

The USDA entry is "Beverages, Protein powder whey based" — a formulated retail product, not an isolated ingredient. It reports 12.5g of carbohydrate and 469mg of sodium per 100g alongside that iron, which is the signature of a blended, often fortified powder rather than pure whey. Fortification is the most likely source of the iron, and a number that comes from what a manufacturer added is not a property of the food. We are publishing it with that caveat rather than dropping it, so that if your own tub reports something different, you know why.

Why we cannot give you a per-scoop figure

Every figure above is per 100g, because scoop weights are not in this dataset — both foods are stored on a 100g basis and nothing records what a given brand's scoop holds. Rather than invent one, here is the method: for a scoop of x grams, multiply the per-100g figures by x/100. A 30g scoop would be 0.30 × 78.13g = 23.4g of protein and 0.30 × 381 = 114 calories. Check the number on your own tub — scoops range widely, and commercial isolates run considerably higher in protein and lower in carbohydrate than this generic USDA entry.

The same applies to yogurt: a 170g pot is 1.70 × 9.95g = 16.9g of protein and 1.70 × 73 = 124 calories, if your pot is 170g.

So is the powder worth it?

For hitting a protein target inside a calorie budget, whey is about 50% more efficient — not eight times. That is a real advantage and a modest one. It matters most when the calorie budget is genuinely tight or when 201g of yogurt is more food than you want; it matters least when you were going to eat the calories anyway.

Greek yogurt brings back calcium and potassium per calorie, far less sodium, and it is food rather than a supplement. The honest summary is that these are closer than the per-100g labels suggest, and the choice is mostly about the shape of the meal. The full side-by-side comparison carries the rest of the macro rows, and the individual pages for whey protein and Greek yogurt have the full nutrient breakdowns.

The dried-versus-fresh trap, in one line

Whenever one food is dried and the other is not, a per-100g comparison is mostly a water measurement. Powder against yogurt, raisins against grapes, jerky against steak — the dried one always wins per 100g, and the only question that matters is whether it still wins after you divide by calories. Here it does, by 1.50×, and on calcium and potassium it loses outright.

Which makes this a harder thing to track than it looks. A powder is weighed and a yogurt is eaten from a pot, so the two arrive in your day in completely different units, and the swap that looked obvious on the label is a 49-calorie decision rather than a transformative one. Sunn settles that from a sentence — you send "a scoop of whey in water" or "a pot of Greek yogurt" and it does the per-gram arithmetic and keeps the day's protein total straight, which is the part that actually decides whether the choice mattered.

More reading: how much protein you actually need, and the same per-calorie computation run across all 183 foods in our database.