10Avoid Overly Ripe Fruit
Bananas are a perfect example of how the ripeness of a fruit influences its glycaemic index. Starch is the principal ingredient in an underripe banana, a low glycaemic-index carbohydrate.
As the banana ripens its starch turns into free sugars, and the glycaemic index increases by 70%, changing the fruit from a Good Calorie one to a Bad Calorie one. Although there have been no scientific studies, the same process is likely to occur with other fruits, such as pears and peaches.
You do not have to eat green, unripe fruit. Rather, choose firm yellow bananas and avoid mushy, brown-spotted ones. Other fruits do not have to be hard; choose soft but not mushy or obviously juicy ones.
Many health bars sell fruit drinks that are freshly prepared in a blender. Frequently, they use overly ripe fruit (so no one will see the condition of the fruit). It is probably best to avoid those that do.