RESEARCH PAPER Diet, physical activity, sedentary behaviour and perceptions of the environment in young adults A. A. Lake,* T. Townshend, S. Alvanides,à E. Stamp§ & A. J. Adamson* *Human Nutrition Research Centre, IHS, Medical School, Newcastle University, Newcastle, UK  Global Urban Research Unit, Newcastle University Newcastle, UK àGeography, Newcastle University, Newcastle, UK §Institute of Health & Society, Newcastle University, Newcastle, UK Introduction Britain has been described as an ‘obese society’ (Fore- sight, 2007). The prevalence of obesity in the UK has tripled over 20 years and continues to increase at an alarming rate (National Audit Office, 2001). The health consequences of being overweight and obesity are high; once developed, obesity is difficult to treat, therefore prevention programs aimed at young people are considered a high priority (Summerbell et al., 2005). Changes in the pattern of body mass index (BMI) between 2 and 25 years appears to have a stronger effect on adult weight than either birth weight and adult life- style factors (Guo et al., 2000). There is a lack of research about the eating habits (Wills, 2005), physical activity and sedentary behaviour patterns in this period of transition from adolescence to adulthood (Nelson et al., 2006). This life stage has been shown to comprise Keywords diet, perceptions of the environment, physical activity, sedentary behaviour, young adults. Correspondence A. A. Lake, Human Nutrition Research Centre, Institute of Health & Society, Medical School, HNRC Newcastle University, Leech Building, Framlington Place, Newcastle, UK. Tel.: +44 1912223828 Fax: +44 1912225581 E-mail: amelia.lake@ncl.ac.uk doi:10.1111/j.1365-277X.2009.00982.x Abstract Background: Few studies have explored both food behaviour and physical activity in an environmental context. Most research in this area has focused on adults; the aim of the present study was to describe perceptions of the environ- ment, diet, physical activity and sedentary behaviour patterns in 16–20 year olds in full-time education (Newcastle, UK). Methods: Participants (n = 73) recruited from a college and sixth-form college completed a UK version of the Youth Neighbourhood Environment Walkabili- ty Survey, which included measures of sedentary behaviour. A validated food frequency questionnaire was completed and a factor applied to produce an esti- mated mean daily frequency of intake of each item, which was converted to nutrient intakes. A rank for Index of Multiple Deprivation (IMD) was assigned to their home postcode. Analysis explored associations between sedentary behaviours and nutrient intake. Results: In this descriptive cross-sectional study, most participants reported being physically active for at least 1 h day )1 on 3–4 (n = 28) or 5–7 days (n = 31). There were no significant differences in nutrient intake according to sample quartile IMD position. Sedentary behaviours were significantly associ- ated with less healthy eating patterns. Higher total energy (P = 0.02), higher fat (P = 0.005), percentage energy from fat (P = 0.035) and lower carbohydrate intakes (P = 0.004) were significantly associated with more time spent watching DVDs at the weekend. Conclusions: This combination of sedentary behaviour and less healthy eating patterns has important implications for long-term health (e.g. the tracking of being overweight and obesity from adolescence into adulthood). Understanding behaviour relationships is an important step in developing interventions in this age group. Journal of Human Nutrition and Dietetics ª 2009 The Authors. Journal compilation. 444 ª 2009 The British Dietetic Association Ltd 2009 J Hum Nutr Diet, 22, pp. 444–454