Protein Content of Yogurt by Milk and Straining Method
What the table shows
Protein in yogurt depends on two things: how much protein the milk started with, and how much liquid whey was removed afterward. Fermentation changes the protein total very little, as the USDA figures below show. Straining does most of the work: the milk proteins stay in the curd, while the acid whey that drains off is mostly water and lactose, with well under 1% protein (Karastamatis et al., 2022).
The first table lists published protein values for milks and yogurts made by different methods. The second is our arithmetic for straining a homemade batch, so you can estimate your own result by weighing the whey.
Protein by milk and straining method
All values are grams of protein per 100 grams of product, which is the same as percent by weight.
| Product | Protein (g per 100 g) | Source |
|---|---|---|
| Milks | ||
| Whole cow milk | 3.15 | USDA FoodData Central |
| 2% cow milk | 3.30 | USDA FoodData Central |
| Nonfat cow milk | 3.37 | USDA FoodData Central |
| Goat milk | 3.56 | USDA FoodData Central |
| Sheep milk | 5.98 | USDA FoodData Central |
| Unstrained yogurt | ||
| Plain whole-milk yogurt | 3.47 to 3.82 | USDA SR Legacy; USDA Foundation Foods |
| Plain nonfat yogurt | 4.23 | USDA Foundation Foods |
| Plain low-fat yogurt | 5.25 | USDA SR Legacy |
| Strained yogurt | ||
| Centrifuge-strained Greek yogurt (lab, whole milk) | 8.6 to 9.6 | Karastamatis et al., 2022 |
| Ultrafiltered Greek-style yogurt (lab) | About 10 | Paredes Valencia et al., 2018 |
| Store Greek yogurt, plain whole milk | 8.78 to 9.0 | USDA Foundation Foods; USDA SR Legacy |
| Store Greek yogurt, plain low-fat | 9.95 | USDA SR Legacy |
| Store Greek yogurt, plain nonfat | 10.2 to 10.3 | USDA SR Legacy; USDA Foundation Foods |
| Labneh, bag-strained, from cow milk (lab) | 8.40 | Atamian et al., 2014 |
| Labneh, bag-strained, from goat milk (lab) | 10.00 | Atamian et al., 2014 |
| Labneh, bag-strained, from sheep milk (lab) | 9.69 | Atamian et al., 2014 |
How to read the table
- Unstrained yogurt is about as high in protein as its milk. Cow milks all sit near 3.2 to 3.4 g. Whole-milk yogurt lands close to that. Sheep milk starts almost twice as high, so sheep yogurt does too.
- Some store yogurts have added milk solids. The federal yogurt standard requires at least 8.25% milk solids not fat and allows other milk-derived ingredients to raise that figure (21 CFR 131.200). That likely explains why some unstrained low-fat yogurts list more protein than milk.
- Straining raises protein about two and a half to three times. Greek yogurts made by centrifuge, ultrafiltration or bag straining all land near 8.5 to 10 g. Greek law, as summarized by Karastamatis and colleagues, requires strained yogurt to reach at least 5.6% protein from cow or goat milk and 8% from sheep milk.
- Fat level shifts protein a little. In the labneh study, low-fat samples averaged 10.65% protein and full-fat samples 8.14%, because less fat leaves more room for other solids (Atamian et al., 2014).
For more on what these grams mean in a serving, see Greek yogurt protein and homemade yogurt nutrition.
Estimating protein when you strain at home
Home straining through cloth or a fine mesh is slower than a factory centrifuge, but the principle is the same. You can estimate your result from one number: how much whey you drained. The table assumes you start with 1,000 grams of whole-milk yogurt at 3.82% protein (USDA) and that the whey carries about 0.6% protein, which sits within the 0.45 to 0.63% Karastamatis measured in centrifuge acid whey. USDA lists fluid acid whey a little higher, at 0.76 g (USDA FoodData Central).
| Whey drained from 1,000 g yogurt | Strained yogurt left | Estimated protein | Closest to |
|---|---|---|---|
| None | 1,000 g | About 3.8% | Regular yogurt |
| 250 g | 750 g | About 4.9% | Thick, spoonable yogurt |
| 500 g | 500 g | About 7.0% | Light Greek style |
| 650 g | 350 g | About 9.8% | Typical Greek yogurt |
| 750 g | 250 g | About 13.5% | Labneh-like spread |
The 650 g row is a useful check. It works out to about 1.9 kg of whey per kilogram of strained yogurt. Karastamatis and colleagues removed 1.8 to 2.75 kg per kilogram and measured 8.6 to 9.6% protein, close to the estimate (Karastamatis et al., 2022). The same study found that chilling yogurt for 24 hours before straining gave about 8% more strained yogurt and about 11% less whey.
Practical tips: weigh the bowl of whey instead of timing the strain. In the labneh study, bags of yogurt hung in a cooler for 18 to 50 hours, depending on milk and fat level, to reach the same solids content (Atamian et al., 2014). Strain in the refrigerator. Lower-fat yogurts give higher protein per gram for the same amount of whey removed. Starting with sheep milk, which has almost twice the protein, will push the numbers up further. Step-by-step instructions are in how to make Greek yogurt, and ideas for the drained liquid are in whey from yogurt.
Methodology and sources note
Milk and store-yogurt values are USDA FoodData Central lab data. Strained and labneh values come from three peer-reviewed lab studies that each made only two or three batches per condition, so treat them as typical figures rather than exact targets. The home straining table is our own arithmetic from those figures, not a measurement. Actual results shift with milk, culture, heat treatment and how firmly the curd holds its whey.
Related topics
- What is Greek Yogurt?: how it differs from regular yogurt.
- Homemade Greek Yogurt: straining at home, start to finish.
- Skyr Recipe: another high-protein strained style.
- Milk Type vs Yogurt Texture: how each milk sets.
- Best Milk for Gut Health: choosing a milk to start with.
Sources
- Milk, whole, 3.25% milkfat, with added vitamin D (USDA FoodData Central)
- Milk, reduced fat, fluid, 2% milkfat, with added vitamin A and vitamin D (USDA FoodData Central)
- Milk, nonfat, fluid, with added vitamin A and vitamin D (USDA FoodData Central)
- Milk, goat, fluid, with added vitamin D (USDA FoodData Central)
- Milk, sheep, fluid (USDA FoodData Central)
- Yogurt, plain, whole milk (SR Legacy) (USDA FoodData Central)
- Yogurt, plain, whole milk (Foundation Foods) (USDA FoodData Central)
- Yogurt, plain, nonfat (USDA FoodData Central)
- Yogurt, plain, low fat (USDA FoodData Central)
- Yogurt, Greek, plain, whole milk (Foundation Foods) (USDA FoodData Central)
- Yogurt, Greek, plain, whole milk (SR Legacy) (USDA FoodData Central)
- Yogurt, Greek, plain, lowfat (USDA FoodData Central)
- Yogurt, Greek, plain, nonfat (SR Legacy) (USDA FoodData Central)
- Yogurt, Greek, plain, nonfat (Foundation Foods) (USDA FoodData Central)
- Whey, acid, fluid (USDA FoodData Central)
- Karastamatis S, et al. Effect of Modified Manufacturing Conditions on the Composition of Greek Strained Yogurt and the Quantity and Composition of Generated Acid Whey (Foods, 2022)
- Paredes Valencia A, et al. Effect of Ultrafiltration of Milk Prior to Fermentation on Mass Balance and Process Efficiency in Greek-Style Yogurt Manufacture (Foods, 2018)
- Atamian S, et al. The characterization of the physicochemical and sensory properties of full-fat, reduced-fat and low-fat bovine, caprine, and ovine Greek yogurt (Labneh) (Food Science & Nutrition, 2014)
- 21 CFR 131.200 Yogurt (eCFR, U.S. Food and Drug Administration)
