The highs and lows of the Glycaemic Index
Carbohydrates are an essential part of human nutrition. When digested they provide glucose (the simplest carbohydrate) an essential fuel for the brain, red blood cells, the growing foetus, and muscles during strenuous exercise.
However not all carbohydrates are the same, producing various blood glucose responses. Modern diets are different from our ancestors' diet in that carbohydrate digestion is rapid, we eat foods that have a high Glycaemic Index, spiking blood glucose and corresponding insulin levels. In contrast traditional diets from around the world contain slowly digested and absorbed carbohydrate remove foods that have a low Glyceamic Index (GI value). Many experts now believe that high glucose and insulin levels are one of the key factors responsible for heart disease and hypertension.
Since 1981 hundreds of different foods have been tested by themselves and in mixed meals in both healthy people and diabetics. Professors David Jenkins and Tom Wolever from the University of Toronto were the first to introduce the term ‘Glycaemic Index' [GI] to compare the differing ability of carbohydrate foods to raise blood glucose levels. The GI is a scientifically valid way to describe how a carbohydrate food affects blood glucose levels, which in turn affect insulin levels. High GI carbohydrate foods have a dramatic effect on blood glucose levels compared with low GI foods.
Not all carbohydrate foods are created equal; in fact they behave quite differently in our bodies. The glycemic index or GI describes this difference by ranking carbohydrates according to their effect on our blood glucose levels. Choosing lower level GI carbs - the ones that produce only small changes in blood glucose and insulin levels - is the secret to long-term health, reducing your risk of heart disease and diabetes, and is the key to weight management.
Julie Seamer, Naturopath.
