AN ECOLOGICAL APPROACH

Many of the presenters offered illustrations of individual-level energy-balance behavior embedded within a nested set of influences, including the home, organizations, and the physical and policy environments. Presenters focused in detail on different aspects of the food environment and the built environment for physical activity and their influences on energy balance, but it is also necessary to consider the broader picture. What people consume appears to be influenced by a wide array of factors, including availability and convenience, food and nutrition knowledge, agricultural policies, economic incentives, marketing messages, family and cultural customs and preferences, and individual physiology. How and when people engage in physical activity is influenced by many of the same factors, and by the nature of the built environment where they live and work, their public transportation options, and more. Presenters made clear that the various influences on energy balance are important, although they may be difficult to isolate. Furthermore, several presenters emphasized that sectors that may appear to be unrelated to health actually may be relevant and important to efforts to reduce obesity rates.

PROGRESS AND GAPS IN AVAILABLE MEASURES

Measurement strategies and techniques are a critical foundation for research, McKinnon observed, adding that a study may be well-designed and data rigorously analyzed, but if the basic measures, the assessment tools, are not valid and reliable, true associations between exposures and outcomes may not be understood. A relatively recent review of measures of the food and physical activity environments notes that although much progress has been made, further progress is needed (McKinnon et al., 2009). For example, it suggests that refinement of the measurements of environments in low-income and high-risk communities is needed, as are increased rates of validity and reliability testing and/or reporting. Progress since that report was published includes advancement and refinement in geographic analyses, as well as improvements in measures of the food and physical activity environments. The number of studies assessing the association between the food environment and health and dietary behaviors, in particular, has increased substantially in recent years. Nonetheless, there is still a relative paucity of measures with which to systematically measure policies and policy change.

The workshop presentations reflected both these issues and this progress. McKinnon observed that fairly good individual-level measures of diet and physical activity exist, and that environmental measures in these areas are developing that use, for example, surveys, geographic information systems (GIS), diaries, or universal product code (UPC) scanning.



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