The obesity epidemic - Nature via nurture: A narrative review of high-income countries

Abstract

Over the last three decades, the prevalence of obesity has increased rapidly in populations around the world. Despite a wealth of research, the relative contributions of the different mechanisms underlying this global epidemic are not fully understood. While there is growing consensus that the rapid rise in obesity prevalence has been driven by changes to the environment, it is evident that biology plays a central role in determining who develops obesity and who remains lean in the current obesogenic environment. This review summarises evidence on the extent to which genes and the environment influence energy intake and energy expenditure, and as a result, contribute to the ongoing global obesity epidemic. The concept of genetic susceptibility to the environment driving human variation in body weight is discussed.

Keywords: Epidemiology; environmental influences; epidemic; genetic influences; gene–environment interaction; obesity; obesogenic environment; public health.

Figure 1.

Behavioural susceptibility theory: how appetite mediates the interaction between genetic susceptibility to obesity and environmental exposure. Individuals who inherit a set of genes that bestow greater responsiveness to external food cues and/or lower sensitivity to satiety are more likely to overeat in response to an ‘obesogenic’ food environment, and to gain excessive weight. Obesity, therefore, results from a combination of genetic susceptibility to overeating and exposure to an ‘obesogenic’ food environment. Source: Reproduced from Llewellyn and Fildes with permission from the authors.