The Glycemic Index

The glycemic index (g.i.) is defined as the rate blood sugar will rise following the ingestion of a particular test food relative to the ingestion of a standard food (either white bread or glucose).

This concept has totally changed the way we look at carbohydrates. Instead of accepting the theory that the rate of absorption and thus the rate of rise of the blood sugar is simply based on the length and complexity of the sugar being consumed, the actual and true rise of the blood sugar has been determined in a clinical setting with standardised techniques.

Over the past 20 years a great deal of confusion has arisen in using the glycemic index. This has stemed from the use of two seperate standards, namely white bread and glucose.

When glucose is used as the standard, white bread has a g.i. of 70. When white bread is used as a standard it has a g.i. of 100. Therefore all the glycemic index numbers for different carbohydrates will be different based on which standard food (either glucose or white bread) was used.

There is growing support for the standard food to be glucose = 100. So here we refer to all of the foods according to the standard where glucose equals 100. It is possible to convert the glycemic index from the standard of white bread to glucose by using the factor of 0.7.

The G. I. of Basic Foods

This was in contrast to some complex carbohydrates like white potatoes, which had a glycemic index of 85 or white bread that had a glycemic index of 70. Even more concerning was the fact that wheat bread had a glycemic index of 77 and breakfast cereals like corn flakes, bran flakes, and Cheerios had a glycemic index which was very high and some as high as 92.

This destroyed the concept that the rise in blood sugar could be determined solely on whether a carbohydrate was a simple sugar or a complex carbohydrate. The majority of health care professionals did not accept this new concept with open arms.

For years the concept of the glycemic index has been very controversial. There have been many heated discussions at conferences where these two concepts have been discussed. It takes time for a paradigm shift to occur; especially, when it comes to a concept that has been the mainstay of diet counselling for the past century. Studies done in Australia, Canada, United Kingdom and across Europe have now proven beyond any doubt there is tremendous value in the glycemic index.

What Determines the Glycemic Index ?

To help solve our present health care crisis we need to go back to basics and learning to eat again the "Old Fashioned Way". If the food you are eating is something that your grandmother would not recognise then it most likely will spike your blood sugar levels.

Whole Foods versus Processed Foods

We rush to work in the morning grabbing a piece of toast (usually made from white flour or wheat flour), a glass of orange juice, and a cup of coffee on our way out the door. For lunch, we stop by our favorite fast food restaurant and become impatient when our hamburger, fries and super sized coke is not ready within two minutes.

After a long stressful day at work for both husband and wife, a quick call or text is made on their mobile phones to decide who is going to pick up the pizza for dinner that night. Does this sound all too familiar?

The fast, instant food and consumption of highly processed foods is the most dramatic change that has occurred in our society over the past two generations. The health consequences of this change are not just devastating but lethal. Evidence is abundantly obvious to the casual observer at any shopping mall in the developed world.

When you look at the list of the sources of the top 20 carbohydrates in our diets today compiled by a researcher at the Harvard School of Public Health, you begin to realise that the scenario presented above is right on target.

Top 20 Carbohydrates Consumed Today

1. Potatoes (mashed or baked)

2. White Bread

3. Cold Breakfast Cereal

4. Dark Bread (made from Wheat Flour)

5. Orange Juice

6. Banana

7. White Rice

8. Pizza

9. Pasta

10. Muffins

11. Fruit Punch

12. Coca-Cola

13. Apple

14. Skim Milk

15. Pancakes

16. Table Sugar

17. Jam

18. Cranberry juice

19. French Fries

20. Candy

Looking at the glycemic index of these various foods, you soon begin to realize that the majority are very high-glycemic. Much of this is due to the fact that these foods are highly processed and are made with modern-day flour.

Modern flour comes from high-speed rolling mills, which replaced the traditional millstones of the 18th century. The new mills were much more efficient; however, because they generated much more heat, the flour would spoil very quickly. This was primarily due to the oxidation of the embryo of the seed which occurred much more quickly because of the high heat that was produced.

It did not take long for the millers to realize that if they degerminated the grain and also removed the seed coat (called the bran) this oxidation process could be avoided.

The result was superfine, pure white flour, which did not spoil. It was an economic coup. Not only was the bread, bread products, and pastries made from this flour light and tasty but it also had an extra-long shelf life. It soon became a delicacy of the rich; while the old, stone-ground flour with its coarse texture and taste was left to the peasants of the world.

However, we now realise our bodies are able to absorb these superfine particles of white or wheat flour very quickly. This results in a rapid rise of our blood sugar. In fact, white bread and white flour spikes the blood sugar faster than if we were loading sugar directly on to our tongues!

Just think about the amount of processed grains and carbohydrates that are in our diet. White bread, white flour, wheat flour, most rice, cakes, donuts, potato chips, breakfast cereals, fruit juices, sodas, sports drinks, and the list goes on and on.

Now take a look at the glycemic index of whole foods.

Whole foods are defined as those foods that are eaten in their natural state. They are not processed. Some examples of whole foods are apples, oranges, grapes, beans, cauliflower, brussels sprouts, oats, and whole wheat grains. These foods are natural and still contain their natural fibre and natural form.

When you check out these foods on the glycemic index chart, you will find that they are all low-glycemic foods. Therefore, a general principle, although not absolute, is that the more highly processed a food is the higher its g.i.

For those of us who don't have the time or inclination to investigate each item of food, there is a simple rule of thumb.

I once heard a dietician explain that when you are thinking about consuming a particular food just stop for a moment and ask yourself "Would this have been available in the early 1900's?"

"Would my great grandma have even known what this was?"

If the answer is no, there is a good chance that it is high g.i.

Further related reading can be found on the healthy eating pyramid page.

This is particularly pertinent to folks who believe they have symptoms of metabolic syndrome , as wild swings in blood glucose are what triggers the insulin response.

As we now know, this is a condition to be avoided if we have plans on making a few more laps around the sun and no desire to be amongst the statistics of the diabetic or obese populations.

For strategies to help with this objective, please refer to the solutions page.

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