The glycemic index is a measure of the effect that specific foods have on blood sugar. Foods that raise blood sugar induce an insulin response. Insulin is a hormone released by the pancreas to usher the sugar into the cells. A sustained high glycemic load from every meal could cause insulin resistance over the long run. Fortunately, plain yogurt keeps blood sugar low.
Carbohydrate Complexity
In the past, carbohydrates have been classified according to their complexity based on the number of sugar units that they contain. Carbohydrates composed of one or two sugar units such as the common table sugar sucrose were labeled simple carbohydrates, while starchy foods made out of long sugar chains were known as complex carbohydrates. The complexity of the carbohydrate was believed to determine the rate at which it was absorbed into the bloodstream.
Glycemic Index
However, complexity does not always determine the effect upon blood sugar, so the glycemic index was developed as a more nuanced measure of the relationship between carbohydrates and blood sugar, according to the Linus Pauling Institute. Each food is carefully measured and assigned a specific number based on its effect. Anything that is 55 or lower on the scale has a low effect on blood sugar. If a food is between 56 and 69, then it has a medium effect. Anything that has a GI of at least 70 has a large effect.
Yogurt
Plain yogurt has a glycemic index measurement of 14, according to Diabetesnet.com. This is considered low, both in absolute terms and in relation to other foods. By comparison, fruit yogurt has a glycemic index measurement of 36 and whole milk, from which yogurt derives, has a measurement of 30.
Considerations
The low glycemic load present in plain yogurt stems from the fact that it contains little added sugar and refined carbohydrates. According to Dr. Bill Sears, an associate clinical professor of pediatrics at the University of California, regular yogurt has 9 g of carbohydrates, all of which are made from natural sugar. On the other hand, a heavily refined yogurt can contain between 17 and 32 g of added sugar.
Significance
Avoid foods with a high glycemic index. Several studies conducted by organizations such as the American Cancer Society and Shanghai Women's Health Study have found that a high glycemic load is associated with an increased risk of type 2 diabetes, which is closely related with obesity. In a Nurses' Health Study, women with the highest dietary glycemic load had a risk of developing coronary heart disease. Yogurt, as part of a healthful, balanced diet, can help counteract these trends.
