Understanding the Glycemic Index 101

The glycemic index (GI) is a system that has become as important a measurement in weight loss programs as calories and fat grams. Many diets today use the glycemic index of foods as the basis of their recommended food intake.

History of the Glycemic Index

Per Wikipedia's research, the concept of the glycemic index was born in the early eighties by David J. Jenkins and his colleges at the University of Toronto during a study regarding diabetes. The study's focus was to determine what foods were best for people with the disease. Since then, there have been numerous studies involving the concept of the glycemic index which has resulted in the American Diabetes Association supporting it as a valid system for controlling insulin levels.

Glycemic Index Made Simple

In my opinion, the book, "The South Beach Diet Good Fats Good Carbs Guide" by Arthur Agatston, MD, describes the glycemic index the best. It states, "The glycemic index (GI) is a system that ranks foods by how fast and how high they cause blood sugar to rise after eating a particular food."

Every food on the glycemic index is ranked compared to a standard reference food, such as a slice of white bread, which earns the highest value of 100. A food with a high GI ranking is converted to glucose quickly, causing a spike in blood sugar, while a food with a low GI converts slower, and enters the bloodstream more gradually.

Why Does it Matter How Quickly Blood Sugar Rises?

Insulin has one job in your body, which is to maintain glucose levels. So, when blood glucose (sugar) rises, insulin goes to work to bring it down. The more often your blood sugar level rises and falls, the more often you'll feel hungry. If done to excess, this can cause weight gain and insulin resistance as well as a litany of medical conditions including fatigue, high blood pressure, and diabetes. As well, while insulin is rushing through your bloodstream, metabolism of fat stores is put on hold!

Here is the body's sequence of responses after overeating high GI foods:

>You eat a food high on the glycemic index.

>Your blood glucose (sugar) level spikes.

>Your pancreas releases a flood of insulin in response to the high level of blood sugar.

>The insulin does its job and your blood sugar drops to a low level

>Your hunger is triggered due to low blood sugar, so you eat another food high on the GI index.

>Your blood sugar level spikes and insulin responds.

>Your blood sugar level drops and you eat because you are hungry again.

>You gain weight from overeating.

>Your metabolism becomes out-of-whack and you maybe become insulin resistant due to an overworked pancreas. As well, other medical conditions develop.

>You become a candidate for diabetes.

As you can see, eating carbohydrates at the high end of the glycemic index is not the best way to run our body's engine.

The Beauty of Low Glycemic Foods

Okay, now do you get it? Do you understand why you can eat a wheel barrow full of pretzels or jelly beans (both high on the glycemic index) and still feel hungry? Doesn't it make sense why the whole family feels tired after eating a huge meal consisting primarily of high GI carbohydrates?

But how does eating foods low on the glycemic index help us stay healthy and lose weight, you ask? When we eat a carbohydrate food low on the GI (less than 55), that food takes longer to be converted into blood sugar, so blood sugar rises slowly and insulin responds in kind. There is no spike in blood sugar and insulin, but rather a gradual climb and descent. While this is going on inside our bodies, we are satiated and do not feel hungry, so we go about our business without thinking about food. This is the way our bodies were intended to run.

Enzymes in our gut have a harder time digesting the foods at the low end of the glycemic index, which attributes for the slow release of blood sugar. Some low GI food examples would be apples, broccoli, barley, grapefruit, skim milk or yogurt. Don't make yourself crazy trying to understand why a particular food ranks high or low, just know that it IS ranked as such, after much research. Simply use the index to your benefit.

Glycemic Index Rankings

On many GI lists, foods are simply grouped into low GI (under 55), medium (55-70) and high (over 70). Nutritionists recommend not getting bogged down by the actual number, instead just choosing from the "low GI" foods for the bulk of the carbohydrates you eat..

Now that you understand the effect of eating foods high on the glycemic index, your job is to learn what carbohydrates are at the low end of the index, and to make the right choices. Whenever you choose a food from the high GI list, your conscience should trigger a picture of insulin racing through your blood stream wreaking havoc.

Read this article next:

"Use the Glycemic Index and Lose Weight"
Resources:

Wikipedia - Glycemic index, Insulin Resistance,

"The South Beach Diet Good Fats Good Carbs Guide" by Arthur Agatston, MD, Published 2004, Rodale Inc

South-beach-diet-plan.com

The Official Website of the Glycemic Index and GI Database