I once had a conversation with a bariatric surgeon about weight loss. She was convinced that exercise was the key to sustainable weight loss. I disagreed, saying I thought diet was far more important, noting that most americans ate like trash. She seemed a bit offended that I was disagreeing with her, a doctor specializing in weight loss, about this topic. She was more understanding when I told her that I'd lost a lot of weight simply by cutting out soda. Her look then morphed to something akin to confused horror as I told her that, as a child, I had consistently drank an average of 6 cans of soda per day, every day, and I estimated that this was pretty standard for everyone I knew growing up.