glycemic index

My boyfriend keeps coming home with some new diets. He is worse than any woman. He is overweight, but he is also uncesearily obsessed with it. Anyway, this time he brought a low glycemic index diet. I didn’t understand what exactly it is about. Is there anybody who could give me more info on this glycemic index? Thank you

The glycemic index is a numerical system of measuring how much of a rise in circulating blood sugar a carbohydrate triggers. If a GI is 70 or more than it is high, a GI of 56 to 69 inclusive is medium, and a GI of 55 or less is low. The higher the number, the greater the blood sugar response. Carbohydrates that breakdown quickly during digestion have the highest glycemic indexes. The blood glucose response is fast and high. Carbohydrates that break down slowly, releasing glucose gradually into the blood stream, have low glycemic indexes. This diet you are talking about is based on choosing low GI carbs that are slowly digested and absorbed, producing only gentle rises and falls in blood glucose and insulin levels. It is said that low insulin levels are a key ingredient in weight loss and also in long-term health.