Harvard T.H. Chan – the school of public health – explained that carbohydrates are broken down by the digestive system into sugar.
The glycemic index ranks carbohydrates on a scale from 0 to 100 based on how quickly and how much they raise blood sugar levels after eating.
Foods with a high glycemic index are rapidly digested and cause spikes in blood sugar levels.
Meanwhile, foods with a low glycemic index are digested more slowly, prompting a gradual – and more manageable – rise in blood sugar.