Over our lifetimes, we will eat 70 metric tons of food. So many of our health problems, from type 2 diabetes to dementia, can be traced to problems converting food into energy says Dr Casey Means. She says metabolism is one of the most important and least understood factors in our overall health. Her new book explains the connection between health and cells that aren't creating and using energy properly. The book is called Good Energy: The Surprising Connection Between Metabolism and Limitless Health.