Yogurt can be a confusing item when you’re on a low-carb diet. You can’t simply assume what the carb count will be; you have to read the label of every container and note what is listed as the serving size.

While you might think plain yogurt would have the same amount of carbohydrate as the milk it was made from, this also turns out to be incorrect. Knowing why the carbohydrate content varies for yogurt can help you avoid some of the pitfalls and know what to look for when choosing a yogurt lower in carbs.

Typical Carb Counts for Plain Yogurt

A 6-ounce serving of plain yogurt contains these typical carb counts:

• Whole milk Greek yogurt: 7 grams of carbohydrate
• Whole milk yogurt: 8 grams of carbohydrate.
• Low-fat yogurt: 12 grams of carbohydrate
• Nonfat or skim milk yogurt: 13 grams of carbohydrate

Quick Tips for Choosing Low-Carb Yogurt

• Choose whole milk plain yogurt, which is less likely to be thickened with milk powder or other carbohydrate additives than nonfat or low-fat plain yogurt.
• Choose plain, whole milk Greek-style yogurt in which the whey has been strained, lowering the carbs.
• Avoid low-fat and non-fat yogurts as they often contain more carbohydrates.
• Avoid flavored yogurts, even those that are artificially sweetened.
• Read the label, each and every time.
• Carefully note the serving size as it may be less than the full container you assume to be a serving.
• Use your own flavorings so you know how many carbs you are adding to the yogurt.

Why Do Carb Counts Vary for Yogurt?

Yogurt is produced by taking milk and adding a culture of friendly bacteria that converts the carb-containing milk sugar, lactose, into lactic acid, which is not a carbohydrate. But the yogurt you buy in the store will have a variable carb count depending on how it is produced.

1. Even Plain Yogurt Isn’t Plain

Plain yogurt often has added ingredients that increase carbs. Nonfat milk powder is often added to thicken nonfat yogurt. Powdered milk contains the milk sugar, lactose; therefore it adds back carbs that the original probiotic bacteria digested while turning milk into yogurt.

Whole milk plain yogurt is naturally thicker, so it is less likely be thickened with powdered milk or other carb-containing thickeners than low-fat or nonfat yogurt. It should be your first choice when you want a low-carb yogurt but compare the label of different brands.

2. Yogurt Is Made by Bacteria That Convert the Carbs in Milk

The friendly bacterial culture that turns milk into yogurt and kefir digest much of the lactose in the milk, reducing the sugar in the product. Dr. Jack Goldberg, the co-author of “The Four Corners Diet,” tested fermented milk products. He found that up to 8 grams of carbohydrate are consumed by the bacteria in a cup of yogurt that contains live cultures. Under ideal circumstances, this would reduce the 12 grams of carbohydrate in a cup of milk to about 4 grams of carbohydrate in the yogurt made from it. However, in commercially produced yogurt, the fermentation process may be stopped before it reaches that low level.

As a result, most yogurt has more than 4 grams of carbohydrate per 6 ounces.

3. Live Cultures in Yogurt Make a Difference for Carbs

While all yogurts are made with live cultures, in many cases these are then killed so the fermentation is stopped in the packaged product. After the bacteria are killed, the carbohydrate level becomes stable. Look for labels that confirm that the yogurt still “contains” live cultures, with the names of at least two kinds of bacteria, such as Streptococcus thermophilus, Lactobacillus acidophilus, L. bifidus, or L. casei.

Most commercial yogurt does not ferment long enough at warm temperatures for the maximum amount of lactose consumption by the bacteria.

Although the process continues slowly after chilling, the vast majority happens in the stage where the yogurt is kept warm.

If a yogurt contains live cultures, the amount of carbohydrate will continue to slowly diminish, even after purchase. By the time the carbohydrate decreases to about 4 to 5 grams per cup, the amount stabilizes because so much lactic acid has been produced that the bacteria go dormant. If you make your own yogurt, it may take as long as 20 hours to get to this point (depending upon temperature).

4. Greek Yogurt: Straining the Whey Reduces Carbs

Most of the lactose in yogurt is in the whey, the liquid part of the yogurt. It is easy to strain much of the whey out of yogurt yourself or buy Greek-style yogurt.

To strain the whey out of yogurt yourself, put a coffee filter in a strainer or colander and put that over a bowl in the refrigerator. It will become thicker and thicker as time goes on, so you can stop when it is the consistency you want.

Eventually, it can reach the thickness of soft cream cheese, often called yogurt cheese. This can be eaten any way you like or mixed with other ingredients for foods such as dips. Another advantage to straining yogurt is that the concentrated yogurt has more protein per cup, as well as less carbohydrate.

A Word From Verywell

When you are making low-carb choices, you will need to pay close attention to the nutrition labels on prepared foods such as yogurt. Find the one that matches your goals and enjoy the benefits of this dairy product.