The glycemic index measures how carbohydrates affect blood glucose. The index ranks foods as high, medium or low based on how glucose and insulin react after consumption of a 50 g portion of carbohydrate. Foods are compared to a standard reference -- glucose, which has a glycemic index of 100. The scale ranges from 0 to 100. According to the Glycemic Index Foundation, low GI diets are associated with improved glucose levels in people with diabetes, help with weight control and reduce insulin levels and insulin resistance.
Factors of Low GI Foods
Following a low GI diet entails choosing foods that have a low or medium GI. The GI of a food is mainly affected by fat and fiber. Foods high in fat and fiber take longer to digest, thus slowing the rise in glucose. Foods that are fresh tend to have a lower GI. Fruits and vegetables that are over ripe have a high GI because of the breakdown of sugar in the food. You can cook foods like pasta for a shorter period of time to maintain a low GI level.
Glycemic Load
Glycemic load is a system that ranks foods based on GI and portion size. GL is the sum of GI and the amount of carbohydrate divided by 100. GL was developed because the GI did not take into account portion size of foods. For example, watermelon has a high GI of 72 but the GL is 4. This takes into account that a typical serving of watermelon is less than 50 g, which results in less of an impact on blood glucose. Both the type of carbohydrate and portion size affect blood glucose levels.
Following a Low GI Diet
Choosing to follow a low GI diet requires a person to closely monitor carbohydrate intake and substitute low GI options for high GI foods. There is no counting system. Followers should choose foods that have a low GI -- 55 or less -- or medium GI -- 56 to 69. Low GI foods include quinoa, basmati rice, sweet potatoes, corn, lima beans, non-starchy vegetables, most fruits and oatmeal.
Foods to Limit or Avoid
Foods with a GI greater than 70 are categorized as high. The body rapidly digests high GI foods, resulting in a spike in glucose levels. Processed foods generally have a high GI. White bread, white flour, pretzels, potatoes, corn flakes, puffed rice, bran flakes, melons and pumpkin are examples of high GI foods.
Who Should Follow a Low GI Diet?
Carbohydrate awareness is necessary for proper management of blood glucose levels, therefore the GI diet is widely prescribed for people with diabetes. It is an alternative to the more common carbohydrate counting plan. The American Diabetes Association recommends balancing carbohydrate intake with physical activity and pills or insulin to further maintain healthy blood glucose levels.
