What is the Glycemic Index?

You have probably heard of the term "glycemic Index" (GI) used in a variety of Venues from the neighborhood gym to the latest diet.

Let's sift through the science about the GI diet…

Carbohydrates are breads, cereals, pastas, fruits, vegetables and sugars. These provide energy for your body. The simplest form of carbohydrate is glucose, which fuels your body's organs and tissues. When you eat a carbohydrate food, it raises your blood glucose (blood sugar) to a certain level. The GI is a tool to help rank different carbohydrates and their effect on blood glucose levels on a scale from 0-100. Low GI foods contain slowly digested carbohydrates and produce a gradual, low rise in blood glucose levels, while high GI foods contain rapidly digested carbohydrates and therefore produce a large, rapid rise and fall in blood glucose levels. Examples of high GI foods are cornflakes, white bread and white rice.These are usually highly processed and refined carbohydrates. Low GI foods are vegetables, whole wheat, dried beans like navy beans and lentils, and other complex carbs that haven't been overly-processed.

When you eat a high GI food, it is a little like surging to the top of a roller coaster ride: your blood glucose rapidly rises, your insulin output spikes, and glucose uptake occurs in your muscle tissue and fat storage. Then, as if the roller coaster is plummeting down, your blood glucose drops and counter-regulatory hormones are released, putting you into reactive hypoglycemia (low blood sugar). It's at this time that your appetite is stimulated and you may crave high-carb foods to help get your blood sugar levels back up. There's no roller coaster ride when you eat a low GI food because the rise in blood sugar and insulin is gradual.

The British Journal of Nutrition, in September 2010 found that low GI diets produced better blood sugar control in people with diabetes. The New England Journal of Medicine will publish a report soon to support the increasing evidence that low GI diets help with weight control and reduce the risk of cardiovascular disease.

Are there any drawbacks to the lower GI diet?

• Charts are required to look up values
• Only carb-containing foods are considered, not fat or protein.
• Some nutrient-rich foods are high GI, while some nutrient-poor foods are low GI. Ex. chocolate has a lower GI than oatmeal.
• The GI effect of a food is different when it is eaten alone, compared to when it is combined with other foods, such as in a sandwich or meal.

Tips for eating a low GI diet:
There are still plenty of reasons to strive for eating more low GI foods.

• Use the GI to help chose the right starchy foods; don’t worry about the GI of fruits and vegetables.
• Fill half your plate with non-starchy vegetables or salad.
• If you are eating a high GI food, eat a smaller portion and combine it with low GI foods.
• Include healthy fats and lean proteins at each meal to lower the GI of the meal.
• Remember to make nutrient-rich food choices; it’s not only about how low you can go with the GI.
• Switch to a low GI bread full of whole grains.
• Swap refined breakfast cereals, such as cereal flakes, for a lower GI choice like oats or bran.