The low glycemic index (GI) diet centers around a taxonomy of carbohydrates that classifies some foods as healthier than others. Proponents argue that the GI diet can help you lose weight and ward off chronic illness — without counting calories or cutting carbohydrates. The underlying premise behind the GI diet claims that your body metabolizes different carbohydrates at different rates. A carbohydrate that is consumed too quickly can cause unhealthy spikes in blood sugar. The diet purports that a healthier diet is composed of foods that will release sugar slowly and evenly. If you think the GI stands for good idea, here is a guide to the basics of a low glycemic index diet:
Glycemic index rankings
The glycemic index ranks foods with carbohydrates according to their effect on your blood sugar, which indicates the rate at which you are processing food. Each food receives a score of zero to 100. Higher numbers indicate the foods that are more likely to cause your blood sugar level to spike. A white baked potato with the skin on has a GI of 69. On the other hand, an apple has a GI of 34. The GI of raw apple is markedly lower, which suggests that it will provide energy to your body at a steadier pace than the potato. Many GI diet books include rankings on common foods, and a comprehensive list of over 1,600 foods can be found online at the University of Sydney’s GI database.
Low versus high GI
The University of Sydney provides quick guidelines for GI rankings. High GI foods score 55 or over and should be eaten in moderation. Some examples of high GI foods are certain types of honey, mashed potatoes and white rice. Low GI foods have a score below 55, and they include foods like carrots, raw apples and skim milk. Additional factors can change a food’s GI score. How the food is cooked may raise or lower its GI score. Any variations on the type of food, like red versus white potatoes, can result in a GI change. Even the state of a food, such as whether a banana is ripe, will produce a different GI ranking.
What to eat
GI rankings provide general guidelines as opposed to a strict daily menu. A healthy GI diet will favor whole grains over refined carbohydrates; small servings of pasta in whole grain varieties are generally acceptable. White bread should be substituted for whole grain, sourdough or stone-ground flour options. People following the diet should also eat more beans, lentils, nuts and seeds, as well as fresh fruits and vegetables. Common high GI foods that should be avoided include potatoes and sugary drinks.
With respect to the GI diet’s effect on weight loss, studies have shown mixed results, according to the MayoClinic. Evidence suggests a GI diet can contribute to weight loss in part because dieters end up eating more fiber and protein-rich foods. Nonetheless, the GI diet may pose some nutritional follies as the index ignores important factors such as the food’s saturated fat content. A report by the American Diabetes Association suggests that a GI diet may be helpful for people with diabetes because the disease affects the body’s ability to regulate blood sugar levels.