We’ve come to know Greek yogurt as a hero of healthy breakfast. Unfortunately, as with most products, the mass demand for Greek yogurt has resulted in a lot of cheap knockoffs. While Greek yogurt should technically be made by straining the whey from standard yogurt, a large amount of products on grocery store shelves in the US aren't made this way at all. It all comes down to one pretty important fact: There is no legal definition of “Greek yogurt” in the United States. 

The FDA lists a definition of requirements for specific standardized yogurt: “food produced by culturing one or more of the optional dairy ingredients” (listed later in the definition as “cream, milk, partially skimmed milk, or skim milk used alone or in combination”) “with a characterizing bacterial culture that contains the lactic acid-producing bacteria, Lactobacillus bulgaricus and Streptococcus thermophilus.” In addition to saying that yogurt may contain various concentrated or dehydrated lactose products, the definition also states yogurt may include other ingredients under the large umbrellas “nutritive carbohydrate sweeteners” “flavoring ingredients,” “color additives,” and “stabilizers.” However, considering that there is no standard for what makes yogurt “Greek,” some companies feel that as long as they’re producing a product that can legally be sold as yogurt, there’s no need to maintain convention of thickening through straining alone, and opt for added thickeners.

To show the degree to which recipes for Greek yogurt differ, I’ll compare two popular brands, Chobani and Yoplait

Chobani is a loud supporter of pure Greek yogurt made with “real ingredients,” “natural sugars,” and growth hormone-free milk. They make their plain yogurt by starting with either nonfat yogurt (made from cultured pasteurized nonfat milk), or whole fat yogurt (made from cultured pasteurized nonfat milk and cream.) The remainder of the ingredients in both types of yogurt reads: “live and active cultures: S. Thermophilus, L. Bulgaricus, L. Acidophilus, Bifidus And L. Casei.” Both yogurts have 4 grams of sugar per 5.3-ounce serving, which occurs naturally from the milk’s lactose. Chobani’s flavored yogurts contain the gelling agents locust bean gum and fruit pectin, which provide stability for the fruit mixtures in the products. According to the ingredients listed on their website, Chobani does not use preservatives or artificial sweeteners.

Yoplait doesn’t shy away from using added thickeners and preservatives in certain types of their Greek yogurt. Their plain Greek yogurt (only available in nonfat) ingredient list is relatively minimal, (“cultured pasteurized Grade A nonfat milk, yogurt cultures (L. bulgaricus, S. thermophilus),”) but does contain a preservative: "0.5% or less of: potassium sorbate added to maintain freshness," their website states. Yoplait’s flavored yogurts, Greek 100 Protein and Greek Regular, both contain the thickeners modified corn starch and pectin, as well as the artificial sweetener sucralose, also known as Splenda.

Whether Greek yogurt contains corn starch or locust bean gum likely won’t make too much of a difference to the average consumer's stomach. However, considering that most brands of sweetened Greek yogurt have a super-high sugar content, a good rule of thumb for all yogurt eaters is to buy plain, and sweeten it yourself with just a bit of honey, syrup, or jam.