Avoid potato chips. Watch less TV. Run more. Get surgery. You’ve heard dozens of reasons about why people get fat, and what they should do about it. But today’s guests have some theories about obesity that might not sound so familiar. Biochemist and author Sylvia Tara always had trouble staving off pounds—and then she learned about some truly surprising causes of weight gain. Journalist Gary Taubes thinks obesity can mostly be blamed on one single ingredient. And he thinks that another very popular theory about what leads to obesity is screwing over research into the condition.