Obesity is a significant health and social problem which has reached pandemic levels. The obesogenicity of an environment has been defined as ‘the sum of influences that the surroundings, opportunities, or conditions of life have on promoting obesity in individuals or populations’.¹ Prevention and treatment of obesity has focused on pharmacological, educational and behavioural interventions, with limited overall success. A novel and a longer-term approach would be to investigate the environments that promote high energy intake and sedentary behaviour; this has not yet been fully understood. The obesity epidemic has attracted attention at all levels, from general media interest to policy and practice from health and other professions including urban designers and planners. Shaping the environment to better support healthful decisions has the potential to be a key aspect of a successful obesity prevention intervention. Thus in order to develop effective environmental interventions, in relation to obesity, we need to understand how individuals, and different groups of individuals, interact with their environments in terms of physical activity and food intake.

Grey literature includes a range of documents not controlled by commercial publishing organisations. This means that grey literature can be difficult to search and retrieve for evidence synthesis. Much knowledge and evidence in public health, and other fields, accumulates from innovation in practice. This knowledge may not even be of sufficient formality to meet the definition of grey literature. We term this knowledge ‘grey information’. Grey information may be even harder to search for and retrieve than grey literature. On three previous occasions, we have attempted to systematically search for and synthesise public health grey literature and information—both to summarise the extent and nature of particular classes of interventions and to synthesise results of evaluations. Here, we briefly describe these three ‘case studies’ but focus on our post hoc critical reflections on searching for and synthesising grey literature and information garnered from our experiences of these case studies. We believe these reflections will be useful to future researchers working in this area. Issues discussed include search methods, searching efficiency, replicability of searches, data management, data extraction, assessing study ‘quality’, data synthesis, time and resources, and differentiating evidence synthesis from primary research. Information on applied public health research questions relating to the nature and range of public health interventions, as well as many evaluations of these interventions, may be predominantly, or only, held in grey literature and grey information. Evidence syntheses on these topics need, therefore, to embrace grey literature and information. Many typical systematic review methods for searching, appraising, managing, and synthesising the evidence base can be adapted for use with grey literature and information. Evidence synthesisers should carefully consider the opportunities and problems offered by including grey literature and information. Enhanced incentives for accurate recording and further methodological developments in retrieval will facilitate future syntheses of grey literature and information.

Aims: Obesity is one of the most significant global health and social problems, with rates rising dramatically over the past few decades. While the basic drivers of obesity are obvious (more energy consumed than expended), the causes are multifactorial and complex. A decade ago, it was suggested that exploring the ways in which the built environment influenced physical activity and dietary behaviours might provide fertile ground for investigation. This article overviews current evidence and, in particular, emergent themes that are of significance for the United Kingdom. Methods: This article is based on literature extracted from keyword searching of electronic databases. A timeframe of 2006–2016 was used. Results: In the past decade, the research base has grown significantly; while frustratingly some results are still inconclusive or contradictory, it might be argued enough evidence exists to act upon. Themes such as the importance of the journey to school for young people and the multiple environments in which people spend their time are examples of where real progress has been made in the evidence base. Conclusion: Progress towards real change in policy and practice may seem slow; however, the opportunities afforded for health and planning professionals to work together provide a step towards the whole systems approaches to tackle obesity that are desperately needed.

Food prepared out-of-home tends to be less healthful than food prepared at home, with a positive association between frequency of consumption and both fat intake and body fatness. There is little current data on who eats out-of-home food. We explored frequency and socio-demographic correlates of eating meals out and take-away meals at home, using data from a large, UK, population representative study. Data were from waves 1–4 of the UK National Diet and Nutrition Survey (2008–12). Socio-demographic variables of interest were gender, age group, and socio-economic position. Self-reported frequency of consuming meals out and take-away meals at home was categorised as: less than once per week and once per week or more. Analyses were performed separately for adults (aged 18 years or older) and children. Data from 2001 adults and 1963 children were included. More than one quarter (27.1%) of adults and one fifth (19.0%) of children ate meals out once per week or more. One fifth of adults (21.1%) and children (21.0%) ate take-away meals at home once per week or more. There were no gender differences in consumption of meals out, but more boys than girls ate take-away meals at home at least weekly. The proportion of participants eating both meals out and take-away meals at home at least weekly peaked in young adults aged 19–29 years. Adults living in more affluent households were more likely to eat meals out at least once per week, but children living in less affluent households were more likely to eat take-away meals at home at least once per week. There was no relationship between socio-economic position and consumption of take-away meals at home in adults. One-fifth to one-quarter of individuals eat meals prepared out-of-home weekly. Interventions seeking to improve dietary intake by reducing consumption of out-of-home food may be more effective if tailored to and targeted at adults aged less than 30 years. It may also be important to develop interventions to help children and adolescents avoid becoming frequent consumers of out-of-home food.

Background Links between diet in childhood and the prevention of disease in adulthood have been established. This longitudinal dietary survey provided quantitative evidence of dietary change from adolescence to adulthood, in Northumberland, England. Objective To report longitudinal dietary change in 198 respondents between the ages of 12 and 33 years, to explore dietary ‘tracking’ between the same time points and to describe the effects of gender, socio-economic status and location on dietary change. Methods A longitudinal study recorded dietary change from adolescence to adulthood. Two 3-day food diaries were collected in 1980 and 2000 from the same 198 respondents. Foods consumed were assigned to the five categories in the Balance of Good Health (BGH). Demographic and socio-economic information were obtained in 1980 and 2000. Results Intakes of foods containing fat and/ or sugar and milk and dairy foods decreased (p < 0.01 and p < 0.031, respectively), while intakes of fruits and vegetables increased (p < 0.01). Intakes of bread, other cereals and potatoes (p = 0.002, r = +0.219); fruits and vegetables (p < 0.01, r = +0.256) and meat, fish and alternatives (p = 0.026, r = +0.158) ‘tracked’ from adolescence to adulthood. Men had increased intake from meat, fish and alternatives and decreased milk and dairy foods more than female respondents (p = 0.003 and p = 0.019). Respondents who had moved away from Northumberland had a greater increase in intake of fruits and vegetables compared with those who remained in the local (p = 0.010). Individuals who had moved to a lower socio-economic group had increased their intake of bread, other cereals and potatoes (p = 0.040). Conclusion Food intake changed considerably in a direction more in the line with current dietary recommendations. Food intake in adolescence was a significant, but not strong, predictor of intake in adulthood. Dietary change is influenced by variables including gender, location and socio-economic status.