Obesity: a historical account of the construction of a modern epidemic
This thesis describes the development of the idea of an 'obesity epidemic' that figures prominently in contemporary public health discourse. It uses conceptual approaches from Science and Technology Studies and the history of medicine to analyse changing ideas about obesity, particularly as formulated and mobilised by British researchers from the 1960s onwards, to show how excess body weight became understood as a significant public health problem in this period. The thesis begins by describing the post-war refocusing of medical attention in developed countries from infectious diseases, the rates of which are falling, to chronic disease such as heart disease, diabetes, cancer and stroke. Heart disease, in particular, became seen as an 'epidemic'. After World War II, increase research funding by the American government made possible the development of a new research method - the long-term prospective epidemiological study - and a new way of understanding chronic diseases as caused by risk factors such as high blood pressure, cigarette smoking and high blood cholesterol. Excess body weight was includes in this list of risk factors, and so became an object in increased medical attention. The thesis then outlines how a new public health coalition was formed around obesity in the 1970s by British biomedical researchers working on topics in the fields of nutrition, diabetes and coronary heart disease. It describes the development of what I call the 'individual paradigm' of obesity which characterises the condition as an individual problem that leads to heart disease and mechanical complaints and is treatable by weight loss diets. It then describes two key features of British obesity science in the 1980s and 1990s. The first of these is the adoption of the Body Mass Index and the standard cut-off points that are used to define overweight and obesity, which together facilitate the collection and dissemination of data on changes in average body weights, The second is the energy balance model of weight regulation, which served to unify the diverse disciplinary approaches to biomedical research incorporated into this new knowledge, but which could not account for the high rates of failure acknowledged as occurring with conventional treatments such as weight loss diets, anorectic drugs and bariatric surgery. The thesis describes how researchers in the field of obesity science than extended their institutional research to participate in the production of a series of reports for the World Health Organization, including one on the global epidemic of obesity published in 2000. This new platform, combined with data produced by prospective studies, enabled them to disseminate a new understanding of obesity and overweight - what I call the 'environmental paradigm' - which characterises it as a global health problem associated with an increased risk of many diseases and caused by structural factors such as inappropriate diet and sedentary lifestyles. Despite refocusing attention of structural determinants of ill health, however, public health experts were constrained by considerations of political practicality and commercial interest when calling for preventive measures in the areas of diet and physical activity. The thesis concludes by considering the different ways in which scholars have theorised the epidemiological transition from infectious to chronic disease. Drawing on approaches from the health inequalities literature, it argues that the conventional framings of chronic disease epidemiology have tended systematically to obscure structural links between obesity and other forms of diet-related ill health on the one hand, and relative poverty on the other.