Dear Dr. Mirkin,

Do all sugared beverages increase risk for diabetes?

Dr. Mirkin: Young women who drink five sugared colas per week are 22 percent more likely to develop diabetes during pregnancy (Diabetes Care. December 2009).

In this study, no association was found for other sugar-sweetened drinks.  However, most studies show that all sugared drinks increase risk for diabetes.  For example, several studies have shown that eating fruit is associated with protection from diabetes, while drinking fruit juice increases risk (Diabetes Care, July 2008; Archives of Internal Medicine, July 2008; American Journal of Clinical Nutrition, July 2008).    

When food enters your stomach, the pyloric valve at the end of the stomach closes and prevents solid material from entering your intestines. Then your stomach contracts and mixes the food until it is turned into a soup. Only the liquid soup is allowed to pass into the intestines.  So solid sugared foods stay in your stomach for a while, but liquid sugar passes immediately into your intestines and subsequently into your bloodstream to cause a high rise in blood sugar, which increases risk for diabetes.

On the other hand, during exercise, it is usually safe to take sugared drinks.  Your exercising muscles draw sugar so rapidly from your bloodstream that blood sugar levels usually do not rise too high.  So my rule is to drink sugared beverages only while exercising.