All about the g.i. factorThe glycaemic index concept (the G.I. factor) was first developed in 1981 by Dr David Jenkins, a professor of nutrition at the University of Toronto, Canada, to help determine which foods were best for people with diabetes. At that time, the diet for people with diabetes was based on a system of carbohydrate exchanges or portions, which was complicated and not very logical. The carbohydrate exchange system assumed that all starchy foods produce the same effect on blood sugar levels even though some earlier studies had already proven this was not correct. Jenkins was one of the first researchers to question this assumption and investigate how real foods behave in the bodies of real people. Jenkins approach attracted a great deal of attention because it was so logical and systematic. He and his colleagues had tested a large number of common foods. Some of their results were surprising. Ice cream, for example, despite its sugar content, had much less effect on blood sugar than ordinary bread. Over the next fifteen years medical researchers and scientists around the world, including the authors of this book, tested the effect of many foods on blood sugar levels and developed a new concept of classifying carbohydrates based on the glycaemic index (G.I. factor) of a food. For some years the glycaemic index was a very controversial area. There were avid proponents and opponents of this new approach to classifying carbohydrate. The two sides almost came to blows at conferences aimed at reaching a consensus. Initially, there was some criticism which was justified. In the early days, there was no evidence that G.I. factors for single foods could be applied to mixed meals or that the approach brought long-term benefits. There were no studies of its reproducibility or the consistency of G.L factors from one country to another. Many of the early studies used healthy volunteers and there was no evidence that the results could be applied to people with diabetes. But now the evidence is in and we know that it is a valid tool and a clinically proven tool in its applications to diabetes, appetite control and sport. To date, clinical studies in the United Kingdom, France, Italy, Sweden, Australia and Canada all have proven without doubt the value of the glycaemic index. Notably, the United States remains one of the last bastions of opposition. This may have more to do with academic politics than science! The glycaemic index (or G.L factor) of foods is simply a ranking of foods based on their immediate effect on blood sugar levels. To make a fair comparison, all foods are compared with a reference food such as pure glucose and are tested in equivalent carbohydrate amounts. Today we know the G.I. factors of hundreds of different food items that have been tested following the standardised method. *22\33\4* «On Line Pharmacy» |
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