Australian researchers have discovered why protein suppresses hunger better than sugary carbohydrates – and the reason may have nothing to do with blood sugar levels. Test subjects ate either a high-protein or a high-sugar snack 3 hours before visiting an all-you-can-eat buffet. Two hours after the snack, blood sugar levels were virtually the same for both groups. Yet the high-sugar snack group still consumed the most food at the buffet. Researchers determined that high-protein meals increased levels of cholecystokinin (CCK), a hormone that promotes satiety, whereas the high-carbohydrate meals increased levels of ghrelin, a hormone that promotes hunger.