The Glycemic Index Diet, which is also called the GI Diet, is a weight-loss plan developed by Rick Gallop, a businessman who had trouble losing weight. Gallop bases his plan on the glycemic index, which measures how your body responds to various foods.
The glycemic index was first described about 20 years ago by David Jenkins, a professor of nutrition at the University of Toronto. “It is the rate at which your body’s blood sugar responds to foods,” explains Katherine Tallmadge, MA, RD, national spokesperson for the American Dietetic Association and author of Diet Simple: 192 Mental Tricks, Substitutions, Habits and Inspirations. “The higher your blood sugar goes [when you eat a food], the higher its glycemic index.”
The Glycemic Index Diet: How It Works
The Glycemic Index Diet is based on the concept that foods with a high glycemic index break down too quickly and leave you feeling hungry, while low glycemic index foods are broken down more slowly and can help keep you satisfied for a longer period of time.
With the Glycemic Index Diet, foods are categorized based on where they fall on the glycemic index and grouped by traffic-light colors:
- Red-light foods are processed grains, high-fat milk, and dried fruits
- Yellow-light foods include vegetable juice, frozen yogurt, and eggs
- Green-light foods are meat, fish, vegetables, and beans
The Glycemic Index Diet: Sample Menu
In the first phase of the Glycemic Index Diet, you eat only green-light foods. A typical meal during this phase of the diet might consist of grilled salmon topped with pesto, grilled asparagus, basmati rice, and a green salad.
When you have reached your goal weight, you can begin introducing some yellow-light foods back into your diet, but red-light foods should still be avoided.
The Glycemic Index Diet: The Pros
There are many positive aspects of the Glycemic Index Diet, including:
Sound weight-loss principles. The Glycemic Index Diet focuses on eating reasonable portions and reducing calorie intake, time-tested strategies for losing weight.
Incorporation of nutritious foods. The foods that are promoted in the Glycemic Index Diet, such as fiber-rich foods, whole grains, fruits, and vegetables, are a healthful part of any weight-loss plan, according to dietitian Elisa Zied, MS, RD, spokesperson for the American Dietetic Association and author of Nutrition at Your Fingertips. “So you are getting nutritious foods and will probably have a smaller portion,” Zied says. “That will create a caloric deficit and help you lose weight.”
Simple recipes. Gallop includes simple recipes, snack and meal suggestions, and a pull-out shopping list in his book, designed to make it easier to adopt the Glycemic Index Diet lifestyle.
Scientific backing. Although using the glycemic index for weight loss is still a controversial topic, some researchers have found the people who consume lower glycemic index foods may reduce their risk of becoming obese and developing heart disease and certain cancers.
The Glycemic Index Diet: The Cons
Some of the drawbacks of the Glycemic Index Diet are:
Categorizing foods as “good” or “bad.” The Glycemic Index Diet’s red-light and green-light lists suggest that all high glycemic index foods are “bad” and all low glycemic index foods are “good.” “Foods that have the low glycemic index tend to be healthier than the ones that have the high glycemic index, but there are exceptions to the rule,” Zied says. In fact, Zied points out that there are many healthful foods, including potatoes, carrots, corn, and 100 percent fruit juice, that are high on the glycemic index, and some unhealthful foods, like potato chips and certain types of candy, that are low on the glycemic index.
Relying too heavily on the glycemic index. “The glycemic index is only one of many indicators of the value of a food,” says Tallmadge, adding that you should also look at a food for its freshness, fiber content, calorie density, and other indicators of its nutritional quality. And researchers are not yet certain that eating low glycemic index foods helps you lose weight in the long run. “The research is sketchy right now,” says Zied. “We just don’t know definitively that this is going to promote long-term weight loss.”
Overall, the Glycemic Index Diet has many of the qualities of a good weight-loss plan, but be wary of all of the restrictions and remember that just because a food has a high glycemic index doesn’t mean it will make you fat.