An experimental pathologist and molecular geneticist, Philip Wood uses gene-knockout technology to study the way mouse genes regulate the metabolism of fat—research that provides insights into the workings of fatty-acid metabolism in humans and what can happen when that metabolic balance goes awry. Based on the classes he regularly teaches to first- and second-year medical students, Wood’s book reviews the individual and public health burden of obesity and clarifies often-used, but often inadequately explained, terms employed in the continuing cultural and scientific debate about excess fat. He explains the role of fat in the healthy body, how fat is made, stored, and burned, and demonstrates how excess fat can lead to an array of metabolic disorders and diseases, from hypercholesterolemia and insulin resistance to diabetes. He reviews what recent research can tell us about specific genes or groups of genes that can lead to specific metabolic disorders. He explains the science behind common weight-loss regimens and why those regimens might succeed or fail, and reviews the complex interplay of hormones, genes, and stress in the way our bodies deal with fat through the life cycle. How Fat Works is a concise, clear, and up-to-date primer on the workings of fat, and essential reading for professionals entering careers in medicine and public health administration or anyone wanting a better understanding of one of our most urgent health crises.