The Glycemic index (GI) is a measurement tool to measure the rate at which the blood glucose or blood sugar level rise when a particular food is eaten. Basically, pure glucose has a rating of 100. So nearer the food is to 100, the higher it's GI rating is. This shows that how quickly the food particular were converted to blood sugar, and how quickly the blood sugar levels will drop. There are two types of GI diets - Low GI diets And High GI diets. Foods with low GI rating will be absorbed more slowly, which is helpful to constant blood sugar levels.

Some popular GI diets:

There are some famous GI diets that are

1) Glycemic Impact diets : The Glycemic Impact diets is one of the most popular diet to come along that is truly sensible and possible to follow for one's entire life. It also lacks many of the excessive foods to avoid that so many diets have.
2) Glycemic load diets : The Glycemic load corrects that figure for serving size or amount consumed, and the total Glycemic load in foods consumed each day should be under 500.
3) South beach diets : There are three phases. In this phases most carbohydrates (such as rice, pasta and breads) must be avoided.There are three meals a day. Meat, shellfish, chicken and fish-along with nuts, cheese(fat-free), eggs, salads and vegetables. There are two subsequent phases that include special meals plan and recipes. The third phrase is about living the lifestyle more than a phase - its about eating healthy foods, and maintaining weight.
4) Nutri-System : The Nutrisystem Nourish program is based on the GI. Carbohydrates on the diets are generally low glycemic. A typical day would include 3 meals and 2 snacks.

Conclusion:

GI stand for Glycemic index, which is a measure of the energy levels of carbohydrates foods and the rate at which body uses them. It seems not all carbohydrates foods are same. The higher the GI, the quicker the food is absorbed and used and the sooner people will feel hungry again. There are two types of GI diets-Low GI diets and high GI diets .