It's a new year, which means we all have diets on the brain. But with so many options out there, how can we parse the good and healthy from the fads? On this episode of Next Question with Katie Couric, Katie gets to the bottom of trendy eating plans like intermittent fasting and keto with Dr. Mark Hyman who explains what they are and how they affect the body. Katie also speaks with health, diet and wellness expert Liz Josefsberg about the psychology behind our food cravings and how making incremental behavior changes can help us stick to our good intentions.