When it comes to adding fruit to your diet, go with the whole fruit but not juice. A Harvard study in the Aug. 29, 2013, BMJ found that drinking a serving of fruit juice every day was associated with as much as a 21% increased risk of developing diabetes. Why? "The juicing processes lead to lower contents of beneficial phytochemicals and dietary fiber. In addition, juice fluids are absorbed more rapidly and lead to more dramatic changes after eating in blood sugar and insulin levels than solid whole fruits," explains senior author Dr. Qi Sun, assistant professor in the Department of Nutrition at the Harvard School of Public Health. The good news is that eating at least two servings per week of whole fruits—especially blueberries, grapes, and apples—was associated with a 23% lower risk of developing diabetes.