Obesity is a major cause of morbidity and mortality from chronic diseases such as cardiovascular and musculoskeletal diseases, some cancers and negative psychological wellbeing (1,2). The prevalence of overweight and obesity is high and ranges from 40% to 60% among adults in developed countries (2,3). In the last two decades there have been marked increases in the prevalence of overweight and obesity (4). Overweight and obesity results in substantial health and economic burdens, and these negative consequences are predicted to escalate as the population ages (5,6).
Overweight and obesity are the result of positive energy balance. Low levels of physical activity and/or dietary behaviours that deviate from recommendations are thought to contribute to the epidemic of obesity. In terms of dietary factors, population trends in overweight and obesity would suggest that energy intake exceeds energy expenditure (7). High energy intakes have been associated with higher fat intakes, greater intakes of energy-dense foods, including takeaway foods, higher intakes of foods providing ‘empty calories’ (e.g. sugar-sweetened drinks), lower intakes of foods and nutrients that may have appetite-controlling properties (i.e. fruit and vegetables, fibre) and meal patterns that interfere with the regulation of energy intakes (e.g. skipping breakfast) (7). Despite the health-related benefits of consuming a diet that promotes a healthy weight, many adults do not consume a diet consistent with these recommendations. Population-level dietary estimates show that fat intakes exceed recommendations by at least 10%, the majority of the population do not consume sufficient fruit, vegetables or fibre and a significant proportion of the population skip meals (8–11).
Given the rapid rise in overweight and obesity among populations of developed countries, many health practitioners and health researchers have postulated that the environment, rather than individual-level factors, may be driving the obesity epidemic. Policymakers are increasingly considering environments for the development of policy, however, have been limited by insufficient research documenting the role of the environment. Recent studies have shown that overweight and obesity cluster within areas, suggesting that shared environments may contribute to a positive energy balance (12–14). The postulated relationships between the environment and weight status is shown in Fig. 1. The current review primarily focuses on environmental factors that may influence dietary behaviours. ‘Obesogenic’ food environments are thought to facilitate high energy intakes by increasing access to stores that promote unhealthy food choices, such as takeaway and fast food shops, convenience stores and other outlets that are less likely to sell healthy food choices (15–17). Areas characterized by obesogenic food environments may also be associated with physical activity environments that promote decreased energy expenditure and sedentariness. The presumed importance of these environmental factors has resulted in a myriad of policies and interventions aimed at improving food environments (4,18,19). Despite widespread support for these policies and interventions, the discourse about their supposed importance has largely been discussed in position papers and narrative reviews, without synthesis of the evidence on how food environments are associated with overweight and obesity and the mechanisms by which environmental factors contribute to overweight/obesity.
Two systematic reviews examining environmental correlates of obesogenic dietary intakes were conducted in 2004 (20,21). At this stage, there were few replicated studies that examined associations between obesogenic dietary intakes and the food environment. Given the increased research activity on environmental determinants of health-related behaviours in recent years, we sought to review the more recent literature on how features of the food environment are associated with both dietary intakes and overweight/obesity to identify factors to be targeted in policy and interventions to reduce overweight/obesity and to ascertain how shared environments may contribute to the obesity epidemic.