The glycaemic index (GI) describes the capacity of a food to raise blood glucose compared with glucose in normal glucose-tolerant individuals. Foods with a high GI may be associated with an increased risk of obesity and the post-prandial hyperglycaemia associated with such foods may also increase the risk of type 2 diabetes mellitus.

Classification Examples
High GI White rice (87), baked potato (85), white bread (80)
Medium GI Couscous (65), boiled new potato (62), digestive biscuit (59), brown rice (58), Porridge (55)
Low GI Fruit and vegetables, peanuts

The glycaemic index is shown in brackets. Glucose, by definition, would have a glycaemic index of 100