What Is Greek Yogurt? Nutrition, Protein & Brand Comparison

A complete working guide to Greek yogurt. We cover the straining process that produces it, why it has double the protein of regular yogurt, lactose levels, the major US brands and what differentiates them, FDA labeling rules ("Greek" vs "Greek-style"), and how to use it in cooking. All product-specific numbers come from USDA's Branded Foods database.

The short answer

Greek yogurt is yogurt that has been strained to remove most of the liquid whey, concentrating the milk solids and protein. The result is a thicker, tangier yogurt with roughly double the protein per gram of regular yogurt, slightly less sugar (lactose is removed with the whey), and a denser texture. Per 100 g, plain non-fat Greek yogurts in the US market range from 16-20 g of protein. The major US brands are Fage, Chobani, Oikos, Two Good, and Dannon's Oikos sub-line, with formulations ranging from milk-only to whey-protein-boosted.

The straining process

Yogurt — regular or Greek — starts the same way. Cow's milk is heated to about 85°C to denature whey proteins, cooled to about 43°C, then inoculated with thermophilic bacteria (Streptococcus thermophilus and Lactobacillus bulgaricus). The bacteria ferment lactose (milk sugar) into lactic acid over 4-12 hours, which lowers the pH of the milk and causes the milk proteins to coagulate. The result is the gel structure that gives yogurt its texture.

At this point, regular yogurt is packaged. Greek yogurt goes through an additional straining step. Traditional Greek production uses cheesecloth or muslin bags hung overnight to drip out the watery whey. Commercial production uses centrifuges that achieve the same separation in minutes: the yogurt is spun, the heavier protein-and-fat solids stay in the bowl, and the lighter watery whey is drawn off.

Roughly 60% of the milk by weight is removed as whey during straining. What remains — the "Greek" portion — contains nearly all the milk's casein protein, much of its calcium, and a fraction of its lactose. The whey isn't wasted: it's sold to protein supplement manufacturers, used as an ingredient in other dairy products, or processed into whey protein powders.

Protein content compared

The doubling of protein density is the headline number for Greek yogurt:

Major US Greek yogurt brands

The US Greek yogurt market is dominated by five brands, each with distinct positioning:

Full side-by-side comparison of Fage vs Chobani vs Oikos Pro

Lactose, fat, and sugar content

Lactose: a 100 g serving of plain Greek yogurt typically contains 4-5 g of lactose, compared to 7-9 g in regular yogurt. This is enough lower that some people with mild lactose intolerance tolerate Greek yogurt when they cannot tolerate regular yogurt. Live cultures in any yogurt also break down some lactose during fermentation, contributing to better tolerance. Greek yogurt is not lactose-free, however.

Fat levels: Greek yogurt is sold in 0% (non-fat, made from skim milk), 2% (low-fat), 5% (typically labeled "Total" without further qualifier in Fage's lineup), and full-fat (10%+, less common in the US). Protein content is very similar across fat levels — straining concentrates milk solids regardless of starting fat. Calories scale with the fat level.

Added sugar: plain Greek yogurt has zero added sugar. The sugars listed on a plain Greek yogurt label (typically 5-7 g per 100 g) are naturally-occurring lactose. Flavored Greek yogurts (vanilla, strawberry, honey, etc.) typically add 6-12 g of cane sugar or honey per cup — sometimes more in fruit-on-the-bottom variants. Read the "added sugars" line on the Nutrition Facts panel to distinguish.

"Greek" vs "Greek-style" yogurt

The FDA does not regulate "Greek" as a defined yogurt style. There is no minimum protein content threshold, no required straining step, and no exclusivity protection for the term. This is unlike some European jurisdictions where "Greek yogurt" is a protected designation tied to actual production in Greece.

"Greek-style" yogurt often signals that the product achieves the thick texture through added starches, pectin, or gelatin rather than through straining. Read the ingredient list:

• True Greek yogurt: ingredients are just cultured milk (skim or whole) plus the bacterial cultures. No thickeners, no gums, no starches.
• "Greek-style" yogurt: contains tapioca starch, pectin, gelatin, or other thickeners alongside milk. Protein content is usually 6-10 g per 100 g — closer to regular yogurt than true Greek.

The major US brands (Fage, Chobani, Oikos plain) all use true straining and have ingredient lists with only milk and cultures. Some private-label and budget brands use the "Greek-style" shortcut.

Greek yogurt in cooking

Greek yogurt is a versatile substitute for higher-fat dairy in many recipes:

• Sour cream replacement — direct 1:1 swap in dips, dressings, baked potatoes, tacos. Lower fat, more protein, same tang.
• Mayonnaise replacement — 1:1 in chicken salad, tuna salad, deviled eggs. Different flavor profile (tangier) but similar texture.
• Buttermilk replacement in baking — thin with milk (about 3:1 yogurt to milk) and use 1:1. Works in pancakes, biscuits, muffins.
• Marinade base — the lactic acid tenderizes meat similar to buttermilk-marinated fried chicken. Common in Indian tandoori and tikka recipes.
• Cheesecake base — replaces part of the cream cheese for higher protein and lower fat. Texture is slightly less dense; flavor is tangier.

Heat warning: yogurt curdles at high temperatures because the milk proteins denature and the proteins clump. For hot sauces or gravies, either temper the yogurt (whisk in a small amount of hot liquid before adding to the pot) or add off-heat at the end of cooking. Stabilized yogurts with added starch curdle less easily but at the cost of the "true Greek" formulation.

Where Greek yogurt fits in a diet

High-protein diets: Greek yogurt is one of the most cost-effective whole-food protein sources, typically delivering 17-24 g per cup for under 150 calories. The protein is high-quality (complete amino acid profile, mix of casein and whey) and the texture works for both snacks and full meals (parfaits, sweet preparations, savory dips).

Calorie-restricted diets: protein density per calorie is comparable to plain chicken breast — about 5-6 calories per gram of protein. Greek yogurt also stays satisfying longer than most equivalent-calorie alternatives because of the casein content (slow-digesting protein).

Low-carb diets: plain Greek yogurt is reasonable at 3-5 g of net carbs per 100 g (mostly lactose). Flavored varieties are not low-carb — typical added-sugar levels add 5-10 g of carbs per cup. Read the label.

Vegetarian diets: yes, ovo-lacto-vegetarian (assuming non-animal rennet — most US brands disclose this). Greek yogurt is one of the higher-protein dairy options accessible to vegetarians.

Related

• Fage vs Chobani vs Oikos Pro: side-by-side comparison
• All Greek yogurts in our database, ranked by Labelgrade
• How to read a nutrition label
• How Labelgrade scoring works
• High-protein collection (all categories)