According to a new review published in the International Journal of Molecular Sciences specific substances (polyphenols) found only in plant-based foods alter the metabolism of sugars in our body - they improve it! These substances apparently slow down digestion of carbohydrates, thus preventing sugar rushes and they also stimulate insulin production. In other words, they help to keep our blood sugar well-balanced.
Foods high in polyphenols include blueberries, strawberries, raspberries, citrus fruits, dark grapes, bilberries, cherries, apples, dark plums and blackberries
Hanhineva et al., 2010. Impact of Dietary Polyphenols on Carbohydrate Metabolism. International Journal of Molecular Sciences. 11 (4) 1365-402.