Pediatric endocrinologist Dr. Robert Lustig is one of the leading voices on how our modern diet of processed foods and high sugar is destroying our health. His latest book, Metabolical  connects the dots between our systems—from medical school to dietitians to even health advocacy groups—and the food that’s giving us chronic disease. In this excerpt, he looks at the foods being pushed on our kids through commercials and even school lunch programs, and what that diet does to their development and long-term health.