The Low-Glycemic Index Diet was developed by Dr. David J. Jenkins, a professor of nutrition at the University of Toronto and later turned into a successful line of diet books by author and former president of the Heart and Stroke Foundation of Ontario, Rick Gallop. According to the publishing company, Virgin Books, the G.I. Diet has sold over two million copies.
G.I. stands for Glycemic Index, a medical term used to measure the speed at which carbohydrates break down in the digestive system to form glucose. Glucose is the body's source of energy - it is the fuel that feeds your brain, muscles, and other organs. Glucose is set at 100, and all foods are indexed against that number. So foods that are quickly digested have a high G.I., and foods that are digested more slowly have a lower G.I.[1]
It has been suggested that it is possible to lower the GI of a meal with a few teaspoons of vinegar.[2] However, this is an inaccurate oversimplification of the research findings of Sugiyama et al. (and other researchers) who have conducted tests on the anti-glycemic properties of vinegar under controlled laboratory conditions. [3]
While almost all such research to date has confirmed that adding vinegar to high glycemic foods reduces glycemic impact, these studies have also shown that the addition of other ingredients (such as common table salt) to a “mixed meal” can negate the beneficial effects of the added vinegar by decreasing the acidity of the mix. Thus{{Or|, the suggestion that simply adding vinegar to any combination of foods lowers the overall glycemic impact of the meal has no scientific basis. The mechanism(s) by which vinegar or other acidic agents reduce the glycemic impact of carbohydrate-rich foods is not presently understood.
In spite of the common belief that table sugar contributes to the development of diabetes, it has medium (55-69) GI that produces lower blood glucose levels than the equal amount of calories obtained from starch and some other carbohydrates. Leading international diabetes associations (e.g., Canadian Diabetes Association CDA) ) recommends that table sugar be part of the diabetic diet (up to 10% of daily caloric intake).
EXAMPLES OF G.I. RATINGS
| High-G.I. | Low-G.I.* | ||
|---|---|---|---|
| Foods | Rating | Foods | Rating |
| Glucose | 100 | Grapefruit Juice | 48 |
| Baguette | 95 | All Bran | 43 |
| Cornflakes | 84 | Oatmeal | 42 |
| Rice Cakes | 82 | Spaghetti | 41 |
The glycemic index is a useful aid for diabetics or for anyone who wishes to control their blood glucose levels. A diet based on foods with low glycemic response has been associated with diabetes management, improved blood lipids(cholesterol), reduced risk of heart disease, and weight management. Not only will foods with a low glycemic index take longer to digest (therefore prolonging satiety) they will also maintain blood glucose levels at a relatively constant state. Foods with a high glycemic index not only digest quickly, they can cause extreme fluctuations in blood glucose.
There are some specific factors to look for in foods that can indicate their glycemic index: Low glycemic foods contain: Fat, Whole grains, Protein, Raw Starches, legumes, vegetables, fruits and dairy products. High Glycemic Foods contain: Refined grains, refined sugars, increased amylopectin: amylose ratio, and often high sugar fruits have a high glycemic index
There are other factors that contribute to a foods glycemic index, such as plant variety, food processing, cooking method and whether the food is eaten by itself or in combination with other foods. There are criticisms of the glycemic index, including how impractical it is. Few foods have been tested for their glycemic index, and the preparation and combination with other foods can alter its glycemic index. There is no requirement to display the glycemic index of a food product, and it is not always easy to predict the glycemic index of certain foods. Switching from a high glycemic index diet to a low glycemic index diet can be made relatively easy. Switching white bread and pastas to whole grain, eating breakfast cereals from oats, bran or barley, add more fruits and vegetables when cooking and reducing potato consumption can all aid in lowering glycemic index.