Choosing whole fruit over fruit juice may help lower your risk for diabetes because whole fruit contains more of the fiber that can help control blood sugar. In one long-term study, women who ate three servings of whole fruit daily had an 18% lower risk of developing diabetes, while women who ate one or more servings of spinach, kale, or similar dark, leafy green vegetables had a 9% lower risk of diabetes.
 
Source: Diabetes Care Journal, Vol. 31, Pg. 1311