The low glycemic index diet (GI Diet) is an approach to health and weight loss rather than a specific plan. To understand this diet you first need to know what the glycemic index is.
Glycemic index is the measure of how carbohydrates affect the level of sugar in the blood. The index ranks foods that contain carbohydrates according to their potential for raising an individual’s blood sugar level. Foods that rank high on the glycemic index tend to raise blood sugar levels faster and higher than do foods that rank lower. In other words, the lower a food is on the glycemic index, the less effect it has on blood glucose and insulin levels.
The glycemic index is a numerical index from 0 to 100. Foods that raise blood sugar quickly are high on the glycemic index, rated 70 or higher. Foods that raise blood sugar moderately are rated from 56 to 69. Foods that raise blood sugar slowly are low on the glycemic index and are rated 55 or lower.
The low glycemic index diet focuses on foods that are low on the glycemic index, such as whole grains, beans, fruits, and vegetables. The diet is based on:
- Increasing whole grains, nuts, legumes (beans and peas), fruits, and non-starchy vegetables in the diet;
- Decreasing (but not necessarily eliminating) potatoes, white rice, low-fiber cereals, white bread, and other high glycemic index foods from the diet;
- Decreasing the consumption of sugary foods, such as cakes, soft drinks, cookies, and candy.
- Choosing fresh fruits and vegetables over canned or processed ones.
Why Glycemic Index Matters
Over time high blood sugar levels can cause damage to your eyes, kidneys, nervous system, and heart. High blood sugar contributes to a number of serious diseases and conditions, including:
- Cardiovascular disease
- Certain cancers
- Gallbladder disease
- Type I Diabetes
- Type II Diabetes
The glycemic index tells you how quickly a carbohydrate food raises blood sugar levels. For good health you want to keep your blood sugar within a certain low range. When you know the glycemic index of foods you can choose the foods that are low on the index, which are the ones that raise blood sugar slowly and not very much. You do not have to know the exact rating of each food; it’s enough to know if it is high or low or in the middle of the index.
The glycemic index is not the only thing you need to know about a particular food to understand its affect on your blood sugar. How the food was prepared, what you eat with the food, and your body’s individual reaction to the food can influence how much and how fast the food changes your blood sugar level. Plus, glycemic index only looks at carbohydrates; the amount of protein, fat, or other elements in a food can alter its impact on blood sugar.
High and Low Glycemic Foods
Low glycemic foods include:
- Legumes, such as dried beans and lentils;
- Non-starchy vegetables, such as broccoli, green beans, and peppers.
- Some starchy vegetables, such as yams and sweet potatoes.
- Some whole grains and cereals, such as oatmeal and whole wheat bread.
- Many fruits, such as apples, berries, dried apricots, and cherries.
Moderate glycemic foods include:
- Fresh apricots.
- Shredded wheat cereal.
High glycemic foods include:
- White bread.
- White rice.
- Some fruits, such as dates and watermelon.
- Some vegetables, including white potatoes.
How to Follow a Low Glycemic Index Diet
When you follow the low glycemic index diet you choose the bulk of your carbohydrates from foods with low and medium glycemic ratings in order to keep your blood sugar from going higher than it should. That doesn’t mean you can’t eat any food from the high end of the scale; just have small amounts and balance them with other foods that rank low.
Glycemic index is not the only consideration when you plan meals for the low glycemic index diet. You also need to consider the overall nutritional value of foods, not just their glycemic index. Some foods that are low on the glycemic index are high in saturated fat or sugar, while other foods that have a high glycemic rating have valuable nutrients. For example, ice cream is a low-glycemic food, but it is full of saturated fat. Many candy bars are rank low, but are full of sugar and fat. Potatoes, on the other hand, are high glycemic, but are good sources of vitamin C, potassium, and fiber.
Because the low glycemic index diet does not take serving size into consideration you also need to add that factor into your meal planning. You cannot eat an unlimited amount of any food, even low-glycemic foods, without gaining weight, which affects blood sugar.
Another variable is how you as an individual react to certain foods and food combinations. Foods that are generally low glycemic can raise blood sugar in some individuals. Because of this you need to pay attention to your own reactions to food when you are on a low glycemic diet.
What the Experts Say
The low glycemic diet is an important tool for helping to keep blood sugar levels under control. It should not, however, be the only tool, experts say. Keeping blood sugar levels under control requires portion control and, for many people, medication.
Following the low glycemic index diet allows some people who have diabetes to reduce or even eliminate their medication. As a side benefit, the diet controls appetite and keeps hunger at bay, both of which help with weight management.
Experts say that the diet has its limits. For one, it only deals with carbohydrates. As mentioned earlier, it does not address portion size or the nutritional values of foods. Nor does it consider the impact of food combinations and food preparation on glycemic values.
Remember, the low glycemic index diet is an approach to controlling blood sugar that can be part of an overall plan. A healthy plan for blood sugar control will provide guidance on exercise, nutrition, and weight maintenance.