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.

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1. Jet injection

It has been known for a long time that it is possible to give some drugs beneath the skin forming a high speed jet stream of fine particles (much like jet injection in the diesel engine) and aiming it close to the skin. The particles go right through and lodge beneath the skin and there may be little sensation or pain in this process.

This method is used for local anesthetics and immunizations. It is also used to give insulin and there are several types of jet injections that are now available. The problem up to date had been that it is difficult to administer an accurate dose and one that could be altered when needed by small amounts. Some people have felt that rather expensive and complex paraphernalia needed for jet injection isn’t worth it just to avoid a fine needle.

2. Nasal insulin

Insulin can be absorbed into the body through the membranes of the nose. There is some research evidence to show that diabetes could be controlled by insulin given this way. The disadvantages – so far – are very large doses are needed which is expensive and wasteful. It is also possible that a reaction could be set up in the nose that would cause an irritation and perhaps interfere with the way the insulin was absorbed.

3. Inhalation of insulin

Insulin can also be absorbed through the lining of the lung. It is possible to make a very fine spray of insulin – like a mist of very fine liquid particles – and this could be inhaled into the lungs where the insulin can be absorbed. This system would work rather like the inhalation of medication of asthma and some lung conditions.

This method would probably take longer to give insulin than to give a simple injection, and has the similar potential difficulties to nasal insulin. Nevertheless there is research going on that might develop this and other techniques for having insulin without a needle.

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