'A rigorous account of the science of energy balance' THE TELEGRAPH We all know someone who seems to eat very little yet cannot avoid weight gain, or someone who eats everything they like while remaining slim. Why? Is it the kinds of food we eat, and when? Are our hormones to blame? Could it be chemicals in our environment? Even specialists are now questioning our understanding of the forces that shape body weight, and we are all more confused than ever. In this book, Keith Frayn, one of the world's leading experts on metabolism, argues that all these challenges are distracting us from tackling the obesity problem in the only way it can be addressed: by rebalancing the disregarded message of 'calories in - calories out'. Taking readers on a deep dive into the real science of energy balance, he reveals how nutrition research has been plagued by the difficulty of really knowing what people are eating and doing; why it is unlikely that some nutrients are intrinsically more fattening than