In this 7-minute video, Dr. Mark Hyman explains the critical role inflammation plays in disease and weight gain. He says inflammation is a good thing because it is a natural way the body protects itself. But when the immune system goes out of balance due to food allergies and poor eating habits, inflammation can block your metabolism, lead to weight gain and ultimately chronic disease. For more information on food allergies and inflammation, please see The UltraSimple Diet Challenge.