Commentary Understanding environmental influences on nutrition and physical activity behaviors : where should we look and what should we count ?

Research interest in the influence of environmental factors on nutrition and physical activity behaviors has surged internationally in recent years. This is evident from a rapidly expanding literature and facilitated by advances in methodological and analytical approaches to assessing multiple levels of influence on health behaviors. However, a number of conceptual challenges complicate research endeavours in this field. The purpose of this paper is to provide a 'state of the science' overview of evidence regarding environmental influences on nutrition and physical activity behaviors. We focus particularly on a number of key conceptual and methodological issues, including: a consideration of how the environment is defined; the selection and operationalization of environmental exposures; and the importance of integrating existing understanding of individual influences on behavior with the emerging data on the role of the environment. We draw on examples from the published literature including our own research studies to illustrate these issues. We conclude by proposing a research agenda to progress understanding of the influences of the environment on population nutrition and physical activity behaviors. Background Over the past decade there has been a growing recognition of the role of 'the environment' in influencing health and health behavior. For nutrition and physical activity behaviors, the emergence of the obesity pandemic has brought this issue into sharp focus. Numerous reviews and reports by expert bodies throughout the world highlight the importance of 'environmental' factors on obesity and obesity-risk behaviors, and in terms of obesity prevention, there have been strong calls to focus on changing the environment [1-3]. The notion of creating supportive environments for health is certainly not new. John Snow's actions to disable the Broad Street pump in order to stem the spread of the cholera epidemic in London in 1854 [4] is the classic example of an environmental intervention to protect health. With regards to obesity, Rimm and White drew attention to the central role of 'the environment' more than 25 years ago when they argued that population obesity was a "product of our environment" [5]. The reemergence of social ecological theory [6,7] and its application to the study of nutrition and physical activity behaviors [8,9] provides a recent example of the shift in focus from individual-level (psycho-social) influences on health to environmental influences. While much has been written about the potential impact of the environment on nutrition and physical activity behaviors, and in relation to obesity risk, existing empirical evidence regarding the importance of environmental factors is at best patchy, with many important nutrition Published: 26 September 2006 International Journal of Behavioral Nutrition and Physical Activity 2006, 3:33 doi:10.1186/14795868-3-33 Received: 23 May 2006 Accepted: 26 September 2006 This article is available from: http://www.ijbnpa.org/content/3/1/33 © 2006 Ball et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.