Why low fat milk has a low GI?

Low-fat milk has a low glycemic index (GI) primarily because it contains lactose, a naturally occurring sugar that is absorbed slowly by the body. The presence of protein and fat in milk also helps slow down digestion and the release of glucose into the bloodstream. Additionally, the overall composition of low-fat milk, with its balance of carbohydrates, protein, and fat, contributes to a gradual rise in blood sugar levels, resulting in a lower GI.