The glycemic index of a food relates to how quickly it is absorbed and how strongly it affects blood sugar and insulin levels, as explained by Harvard Medical School. The higher the GI, the greater effect on insulin. Irregardless of the exact type, nuts are a low-glycemic index, or GI, food. Nuts have only a limited amount of dietary carbohydrate and therefore only a small effect on blood glucose levels. Nuts are a valuable complementary ingredient to high-carbohydrate foods. Adding nuts or nut butters to bread or cereal grains will lower the impact of those starchy foods on blood sugar levels.
Glycemic Index for Nuts
It is more important to know that nuts, in general, are a low-GI food than it is to know the specific GI score for a certain kind of nut. The GI for nuts ranges from 14 for peanuts to 21 for cashews, according to the international table of glycemic index and glycemic load values published in the "American Journal of Clinical Nutrition" in 2002. The GI depends on the relative ability of a dietary carbohydrate to raise or lower blood sugar levels compared with a reference food.
Why Are Nuts a Low-Glycemic Index food?
Nuts are a low-GI food, containing relatively small amounts of carbohydrates compared with other favorite snack foods such as crackers. Low-GI foods are those with a score below 55. The GI of nuts depends on the proportional amount of carbohydrate in a 1-oz. serving. Cashews have 8 g of dietary carbohydrate per 1-oz. serving compared with 5 g carbohydrates in peanuts, which explains the variation in GI score between these two varieties.
Nuts As a Complement
Nuts are high in fat and protein; for example, a 1 oz. serving of almonds contains 160 calories, including 6 g of protein, 14 g of fat and 2 g of carbohydrate. Nuts are not typically considered a dietary carbohydrate, which is why information on the impact of these crunchy, tasty snacks on blood glucose level is scarce. On the other hand, nuts are a good complement to carbohydrate-rich foods because the natural oils (fat) in nuts can slow down digestion and absorption of dietary carbohydrates.
Eating nuts with added sugar or honey will raise the GI score; however, the score will still be less than eating carbohydrate-rich foods such as cookies and crackers with added sugar. Also, roasting or cooking nuts can make what little dietary carbohydrate is available in nuts more available to digestive enzymes, which also increases GI score. Consume raw nuts for the least impact on blood glucose level.