The Biology of Blubber

Dr. Mehmet Oz and Dr. Michael Roizen have answered your most embarrassing health questions and taken you inside the human body.. Now they're here to help you with your "waist management."

In their new book, YOU: On a Diet, Dr. Oz and Dr. Roizen explain the science behind lasting weight loss. "This is an operating system for understanding how your body works in the world around it," Dr. Oz says. "There are things we know biologically that have to happen for a diet to work for you."

Dr. Oz says one of the biggest mistakes dieters make is to dramatically decrease their calorie intake. Instead, Dr. Oz and Dr. Roizen say you should only cut your calories by 100 a day.