Epidemiologic transitions: migration and development of obesity and cardiometabolic disease in the developing world

For centuries, the challenge has been the maintenance of bodyweight in the face of marginal food availability. Since the industrial revolution, energy expenditure related to economic activity and domestic life has fallen progressively as technological innovation has replaced muscular power with labor-saving devices. This fall in activity energy expenditure however has not been associated over this entire period with population weight gain. In the 1970s and the 1980s, there was an abrupt uptick in the rate of rise of relative weight in industrialized countries followed rapidly by developing countries. This has led to high and increasing rates of overweight and obesity in high-income countries worldwide, but also an alarming inclusion of low- and middle-income populations in this obesity epidemic. The precise drivers of these concurrent epidemics are not agreed, but probably include on the one hand an increase in dietary energy intake resulting from the impact of industrialization and globalization on food availability and price. On the other, there is the facilitating underlying status of a steadily falling activity energy expenditure as muscle power as an input into economic production as well as household and leisure activities has been supplanted. The rise in population weight without accompanying linear growth manifests as obesity. The accretion of fat as well as the response to other environmental exposures during progressive industrialization and modernization has evoked an accompanying epidemic of cardiometabolic pathology that has significant impact on health as well as macroeconomics. Given the power and presumed irreversibility of industrialization and globalization, our ability to reverse these obesity epidemics is heavily dependent on new knowledge being developed which gives insight with prevention and therapeutic implications on the proximal and distal drivers of this progressive positive energy balance.