Carbohydrates are digested as sugar before being released into the blood stream, causing an increase in blood sugar, according to Harvard T.H. Chan School of Public Health. A system called the glycemic index classifies carbohydrates based on their impact on blood sugar. The system differentiates simple carbohydrates, which are made of sugars such as fructose and glucose and promote quick spikes in blood sugar, from complex carbohydrates which generally contain more fiber and digest at a slower rate.
As sugar from carbohydrates are transferred to the blood stream, the pancreas produces insulin and glucagon to manage blood sugar levels, states Harvard T.H. Chan School of Public Health. Insulin directs sugar into storage cells which lowers blood sugar, and glucagon assists in releasing stored sugar for the body to use as energy.
Insulin resistance occurs when the body doesn't properly use the insulin it produces or doesn't produce enough to be effective, causing consistently prolonged levels of high blood sugar, according to Harvard T.H. Chan School of Public Health. Eventually the body ceases to produce insulin altogether. Individuals who are insulin resistant are at high risk for developing Type 2 diabetes.
The glycemic index can help individuals manage weight and reduce risk of Type 2 diabetes through its ranking system, explains Harvard T.H. Chan School of Public Health. The index of carbohydrate foods is based on how quickly they are digested and the speed at which blood sugar rises after consuming them. Foods that have a lower glycemic index (55 or less) are better choices for those trying to control blood sugar levels.