Apples are low on the glycaemic index (GI) thanks to their fibre content. This, together with their high flavonoid content, may help to improve insulin sensitivity, which is important both for weight management and preventing diabetes. And because apples are both sweet and filling, snacking on an apple can be a smart way to respond to cravings. Just be sure to eat the whole fruit, peel and all. The fiber will help keep you satisfied.