BACKGROUND INFORMATION: THE GLYCAEMIC INDEX
Nutrition research conducted in the 1970’s showed that different carbohydrates did not have the same effects on blood glucose (sugar) levels after eating. These findings challenged the general assumption that all ‘complex’ carbohydrates (starches) produce lower blood glucose responses than ‘simple’ sugars, and questioned the clinical significance of carbohydrate exchange lists that have regulated the diets of people with diabetes for over three decades. These exchange lists are based on the assumption that portions of different foods containing equal amounts of carbohydrate will produce the same blood glucose response.
Consequently, the glycaemic index (GI) method was developed in order to rank equal carbohydrate portions of different foods according to the extent to which they increase blood glucose levels after being eaten (1). Foods with a high GI value contain rapidly digested carbohydrate, which produces a rapid and large rise and fall in the level of blood glucose. In contrast, foods with a low GI value contain slowly digested carbohydrate, which produces a gradual, relatively low rise in the level of blood glucose (Figure 1).
Figure 1. The two hour blood glucose responses for a high-GI food (white bread: GI value = 70) and a low-GI food (lentils: GI value = 30).
Nadine – 45
Royal Blue – 54
Almera – 53
Chelsea – 53
Bellita – 53
Carisma – 53