The Glycaemix Index (G.I.) of a food is a measure of the effect that the food has on blood sugar levels. A low G.I. value will mean that the food will have a low impact on raising the blood glucose level. Conversely, a high G.I. will mean that the blood sugar levels are elevated in some cases into a 'danger zone' that will result in the need for insulin.

It is recommended that by including carbohydrates which have a low G.I. in the diet, the effect will be more stable blood sugar levels. This will also decrease the possibility of over-eating once the blood sugar levels drop rapidly after the digestion of high G.I. carbohydrates - a phenomenum that can contribute to being overweight (see weight control).

Fruisana Fruit Sugar is classified as being low G.I. as it has a Glycaemix Index of 19, compared to glucose with a G.I. of 100. Table sugar (sucrose) G.I: 65.