While sugary drinks are not the only contributor to the obesity epidemic in the United States, they are a major source of consumed calories and are devoid of nutritional value.
The high glycemic load of sugary drinks provokes insulin resistance in many people, which underlies much of the obesity in our society, and raises the risk of Type 2 diabetes.
Diet soda is also not healthy for us – there is evidence that drinking diet soda may contribute to weight gain by creating changes in our brains that result in an increased desire for sweets, and a study published online in the Journal of General Internal Medicine in January, 2012 found an increased risk of heart attack and stroke among individuals who had a daily diet soda habit.
My biggest concern about diet soda, however, is that people who drink the most of it seem to be in the worst relationships with food.
-- with Marti Lotman

Andrew Weil, M.D., is Founder and Director, Arizona Center for Integrative Medicine at the College of Medicine, University of Arizona, and Director of Integrative Health and Healing, Miraval Resort. He is a pioneer in the field of integrative medicine, which combines conventional medicine with alternative approaches. He received his medical degree from Harvard University. His new book is "True Food: Seasonal, Sustainable, Simple, Pure."