Chronic diseases have rapidly become the leading global cause of morbidity and mortality, yet there is poor understanding of this transition, or why particular social and ethnic groups are especially susceptible. In this book, Wells adopts a multidisciplinary approach to human nutrition, emphasising how power relations shape the physiological pathways to obesity, diabetes, hypertension and cardiovascular disease. Part I reviews the physiological basis of chronic diseases, presenting a 'capacity-load' model that integrates the nutritional contributions of developmental experience and adult lifestyle. Part II presents an evolutionary perspective on the sensitivity of human metabolism to ecological stresses, highlighting how social hierarchy impacts metabolism on an intergenerational timescale. Part III reviews how nutrition has changed over time, as societies evolved and coalesced towards a single global economic system. Part IV integrates these physiological, evolutionary and politico-economic perspectives in a unifying framework, to deepen our understanding of the societal basis of metabolic ill-health.