Advice from professional dietitians is that foods which are eaten as a source of glucose (which is an essential nutrient) should be low GI.

That means that the glucose in them is released slowly during digestion, with corresponding slow insulin secretion. The contrast is with high GI foods in which glucose is released rapidly, with a corresponding rapid spike of insulin secretion - this can proceed to insulin resistance.

Examples of low GI foods include wholegrain bread (not white bread), brown rice (not white rice), brown (not white) pasta as well as many fruits and vegetables.

Eating in this healthy way can help people who are at risk of Type 2 Diabetes as well as other people though (same as for any other food) portion control is also important.