The glycemic index or "GI" is a rating system that predicts how much a certain food or beverage will raise your blood sugar. Yams, often mistaken for sweet potatoes, are a vegetable that is a complex carbohydrate source, used by many bodybuilders and athletes. Whether you are a bodybuilder, a diabetic or someone who eats yams and is just trying to lose weight, you should be familiar with where yams fall on the glycemic index.
Glycemic Index of Yams
The Harvard School of Public Health states that the average yam has a glycemic index rating of 37, plus or minus 8 points. A rating of 37 puts yams in the category of low glycemic index foods. Low-GI foods are thought to have less of an effect on your blood sugar levels.
Yams vs. Sweet Potatoes
Although many people interchangeably refer to yams and sweet potatoes, they are not identical vegetables. While yams have a glycemic index rating of 37, sweet potatoes have a glycemic index rating of 61, plus or minus 7 points. This puts the average sweet potato among foods considered to have a moderate GI and a moderate effect on your blood sugar. The National Library of Congress explains that yams and sweet potatoes are not even botanically related. Even though yams and sweet potatoes look similar, their glycemic index varies significantly.
Significance
The glycemic index rating of 37 for yams makes it an ideal food if you want to keep your blood sugar low and stable. Diabetics are familiar with the glycemic index because they need to keep their blood sugar stable. If you want to lose weight, you should avoid simple carbohydrates and high GI foods that rate 70 and above. When you raise your blood sugar, your body releases insulin to stabilize your glucose levels. This also can lead to fat storage.
Considerations
Keep in mind that the numerical GI value of 37 applies to a yam that contains no added toppings such as apple butter, brown sugar or maple syrup. By adding toppings, particularly other simple carbohydrate sources, you can dramatically increase the glycemic index of a previously low-GI food or meal. The glycemic index is often the scale that distinguishes a "good" carbohydrate source from a "bad" carbohydrate source. According to the Joslin Diabetes Center and Harvard Medical School, carbohydrates, especially simple sugars, have the greatest effect on your blood glucose levels.
