The Glycemic Load
The notes on these pages are the results of many weeks of research from books and the Internet. I have diabetes and needed to know how to try live my life better, thus these notes and NutriDroid! So far I have lost 35 pounds and another 30 to go. I contribute most of this to a new way of eating in which I had to have software to guide me along. NutriDroid was born.
The glycemic index (GI) was studied in 1981 by David Jenkins and Thomas Wolever. They devised a system for classifying carbohydrate-containing foods, according to how fast they raise blood-glucose levels inside the body. Further expansion for the GI was made by the Human Nutrition Unit (HNU) of the University of Sydney in Sydney, Australia in 1995 and to date is the only recorded experiment.
Glycemic Index values are determined experimentally by feeding human test subjects a fixed portion of the food and then testing their blood sugar at specific intervals of time.
The glycemic index method of classifying carbohydrates according to their effect on blood-glucose, replaces the older method of classifying carbohydrates according to their chemical structure of either "simple" or "complex" carbohydrates.
The glycemic index consists of a scale from 1 to 100, indicating the rate at which 50 grams of carbohydrate in a particular food is absorbed into the bloodstream as blood-sugar.
Remember the food has to have carbs to have a GI. The NutriDroid database does not list the GI of every food. We wrote fairly complex data analysis routines to take the date published by the HNU to match it with foods in our main database however not all foods will fit into the food list from HNU.
The glycemic index separates carb-containing foods into three general categories:
- High Glycemic Index Foods (GI 70+), that causes a rapid rise in blood-glucose levels.
- Intermediate Glycemic Index Foods (GI 55-69) causes a medium rise in blood-glucose.
- Low Glycemic Index Foods (GI 54 or less), causing a slower rise in blood-sugar.
The Glycemic Index has its critics. The GI of a food could vary depending on a number of factors such as: ripeness, storage time, cooking method, variety, and a food combination in a given meal. There are other individual dependent contributing factors, such as: insulin resistance, blood glucose levels, and glycemic response.
If you want to know the impact of a particular food on blood sugar and insulin, you need to know the glycemic index and how much of that food you are going to eat. GI ranges are:
Low GI = 55 or less
Medium GI = 56-69
High GI = 70 or more
The Glycemic Load (GL) is a more accurate indicator of carbohydrate conversion and its effect on our blood sugar and insulin levels. The carbohydrate rating tool is rates the glycemic value of food serving sizes. The GL provides a measure of an overall impact on our blood sugar and insulin level.
Low GL = 10 or less
Medium GL = 11-19
High GL = 20 or more
Look at the Glycemic Index for these 3 foods:
Carrot Juice 43
Boiled Carrot 92
Boiled whole grain spaghetti 32
Using the Glycemic Index and choosing from this short list it looks like the spaghetti would be a good choice. However the Glycemic Load shows a different answer:
Carrot Juice 5.7
Boiled Carrot 3.9
Boiled whole grain spaghetti 14.2
Despite the fact that a boiled carrot has a GI of 92, the GL for it is only 3.9. These facts have guided me to watch the load more than the index.
Although the glycemic index was invented originally to help diabetes patients manage their blood-sugar levels, experts now use it as a tool to treat obesity, reduce cravings and appetite swings, and improve eating habits.
Have you ever noticed that you feel lethargic after eating foods that stimulate a large insulin response, such as donuts or candy? How about the couple of beers with lunch? A typical beer has a GI of 120! You are tired because too much insulin is produced in response to such foods, and this excess insulin causes blood sugar levels to drop below normal, resulting in low blood sugar (hypoglycemia) and fatigue.
According to clinical trials, GI diet programs provide an excellent dietary approach for people who want to reduce weight. By advocating the consumption of carbohydrate-rich foods with a low GI-value, and the avoidance of refined carbs, GI diet programs provide dieters with the best of all worlds - better blood glucose control and a highly nutritious eating plan. The health advantages of a low GI diet plan are one reason why it has superseded the low carb diet as the most popular weight loss plan.
The GL should be used as a tool allowing you to choose one food over another in the same food group, the best bread to choose, the best cereal etc. A low GL diet is about eating a wide variety of healthy foods. These are the less processed and wholesome foods that will provide you with carbs in a slow release form.
Choose slow carbs, not low carbs, or a in other words, a low Glycemic Load.