What the Heck is the Glycemic Index… And Why Do I Care?

4/11/2008

The principle of the glycemic index is possibly the most important aspect of healthy nutrition and the most overlooked. I’m amazed how few physicians understand this basic rule of nutrition, and how infrequently the issue is discussed during an office visit.

The glycemic index (GI) uses a score of 1 to 100 to measure the quality of the carbohydrates in a food. High-glycemic foods (score over 70) are not considered to be as good for you as low-glycemic foods (score of 55 or below).

The GI of a specific food is calculated by measuring the physiological response that a human body has when it is eaten. The higher the GI of a food, the more rapidly your blood sugar goes up after eating it and the more rapidly and aggressively your pancreas releases insulin into the bloodstream. Excessive insulin levels in the blood can eventually lead to a condition caused insulin resistance, a major factor in weight gain and the development of diabetes.

Ideally you should eat more foods with a low GI score because they are not digested as quickly and cause a slower, more moderate rise in levels of blood sugar. Foods with a low GI are usually more natural foods like brown rice or whole-grain bread. Highly processed foods like white flour, sugar, or white rice have a high GI.

What are the benefits of eating foods lower on the glycemic index?

• Lower risk of heart disease
• Lower risk for type-2 diabetes mellitus
• Easier weight control and weight loss
• Lower blood cholesterol levels
• Decrease in fatigue and “brain fog”

The general rule is the more processed the carb, the higher the glycemic index, the worse the health effects. This doesn’t mean you have to give up high GI food entirely, but you should try to eat at least one low GI food at every meal.

How can you add more low GI foods to your diet?

• Choose chewy whole-grain bread over airy white breads.
• Breakfast on cereals based on oats and bran.
• Reduce consumption of white potatoes in favor of sweet potatoes.
• Choose basmati or brown rice over plain white rice
• Try quinoa, a very-low-GI grain also safe for those with celiac disease
• Avoid processed white sugars
• Eat more fruits and vegetables, which rank low on the GI scores.

If you take the time to talk with your whole family about the glycemic index, you help them make good food choices. Some of these choices may seem counter-intuitive. I know many parents are shocked to discover that rice cakes--often touted as great healthy snacks--are actually very high in the glycemic index. But that’s how the cookie crumbles!

You can find GI ratings for carbohydrates at www.glycemicindex.com/