Please Explain: Metabolism

Some diets and supplements claim to work by speeding up metabolism. Find out how metabolism works, why it’s essential to life, and whether food, exercise, and supplements really can accelerate it...or slow it down. Dr. Rosalind Coleman is Professor of Nutrition and Pediatrics at UNC-Chapel Hill; Marion Nestle is Professor in the Department of Nutrition, Food Studies, and Public Health at NYU. She's author of several books including, most recently, What to Eat.