My favorite part of the documentary, actually, is the explanation for why whole foods (ideally plants, but not necessarily) are so vastly better for us than processed foods. It’s an easy-to-follow, intuitive argument about how processed food takes advantage of our ancient, innate drive to consume fatty and sweet foods because, in nature, these qualities are signals of high caloric density. And foods rich in calories, of course, were essential to our species’ survival when food was scarce.