O Type of starch in food
In Amylose starch, glucose rings are hooked together and is harder to digest thus have Low GI rank.Amylopectin molecules ,when the starch cools, are more open easer to digest thus has higher GI value.

O Cooking
cooking can increase the GI ranking of a food. For example, cooking swells starch molecules making it faster to digest. A 10 -mints boiled pasta has a higher GI number than a 5-mints boiled pasta.

O Processing of food
Highly processed foods are digested faster and usually have a higher GI number. For instance, cereals usually have a higher Glycemic Index compared to whole grains or legumes.

O Food's fat content
Foods with higher fat content have lower GI rating. Fat content changes how your body digest foods. This shows that Low GI foods are not always the healthiest choice. Potato chips has a lower GI, 75, compared to baked potato, 93.

O Acid content of the food
Acid present in foods slows down the digestion of that food.. Slower digestion means slower rise in blood sugar.