Glycemic Index

Most people believe that they will lose weight provided that they eat fewer calories than they burn. They also believe that all calories are created equal. Neither of these statements is necessarily true. It is now apparent that different foods convert different percentages of calories into fat. This is particularly true concerning carbohydrates. The fat forming ability of different carbohydrates can vary even though they may have the same caloric value.

Our bodies need fuel to perform the minute-by-minute functions that we must perform to exist. Even while we are asleep we need energy. The body prefers carbohydrates which are the most widely consumed fuel. They provide energy more efficiently than fats and protein. Just like cars will not run without gasoline, your body will not perform efficiently with just a limited amount of carbohydrates. At least 60% of your calories should come from carbohydrates. But, as you will find out, just like some forms of gasoline are better than others, some carbohydrates are also better and will result in more efficient performance.

For years carbohydrates have been classified as "simple" and "complex" and we have been told to limit our intake of simple carbohydrates such as sweets, sodas, candy and desserts. It was thought that simple carbohydrates would be absorbed rapidly producing a large increase in your blood sugar level. On the other hand it was assumed that complex carbohydrates would be digested and absorbed slowly and would cause only a moderate increase in your blood sugar level. These assumptions proved to be incorrect. Digestion and absorption do not occur at the same rate for all carbohydrates within a biological grouping. We need to forget the old distinction of simple and complex carbohydrates as they do not reflect the effects of these foods on blood glucose.

A newer system for classification of carbohydrates, the Glycemic Index, takes us nearer to a full understanding of how the body responds to foods containing carbohydrates. This term refers to the relative degree to which the concentration of glucose in the blood rises, after the consumption of food. The reference point is glucose which has a value of 100 and all foods have a value less than this. The higher the number for a particular food, the faster the glucose will get into the bloodstream, and the higher the value is likely to be. For example, honey has a value of 73 and will result in a much faster increase in your blood glucose level than an apple which has a value of only 36. The Glycemic Index can be used to show us the extent to which foods will raise your blood glucose - drastically, moderately, or just a little.

Foods with a high glycemic index cause a sharp rise in your blood glucose level. When this occurs your body "over-reacts" by producing more insulin than it should and you will experience a rapid fall in your blood glucose level and you will probably feel tired and hungry again just a few hours after you have eaten. This is why some foods give you a quick burst of energy and then you are hungry again soon after eating.

Other foods result in a slow steady increase in your blood glucose level, and provided your blood glucose level does not rise too high, they do not cause your body to produce additional insulin. You blood glucose will then return to a low-level in 4 to 5 hours and you will be hungry again. This is one reason why you should not go longer than 4 to 5 hours that you are awake, without eating something.

If your blood glucose is to be maintained within normal limits, you need to learn to eat foods which cause a slow steady rise in your blood glucose level. By doing this you will be more likely to control your energy level and your hunger level throughout the day. The following list of the glycemic index for selected foods will help you make better choices throughout the day. Try to select foods with a lower number.

Reference: International Table of Glycemic Index. Journal Clinical Nutrition, 1995, 62: 871S - 893S. Summarized from original research from 79 different studies from various journals.

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