Urban design and fast-food density affect residents' weight and waist size

In a research article published recently by the American Journal of Epidemiology, Oregon Research Institute (ORI) scientist Fuzhong Li, Ph.D., and colleagues show that a high-density of fast food outlets was associated with an increase of 3 pounds in weight and .8 inches in waist circumference among neighborhood residents who frequently ate at those restaurants.

In contrast, high-walkability neighborhoods were associated with a decrease of 2.7 pounds in weight and 0.6 inches in waist size among residents who increased their levels of vigorous physical activity during a one-year period.

"This is one of the few longitudinal studies that focus on change in individuals' body weight over time in relation to their lifestyle behaviors and immediate living environments," noted Dr. Li. "The uniqueness of this study lies in its environment-person approach which we use to show that health-impeding environments, such as a high density of fast-food outlets, together with residents' behavior, such as eating fast food regularly, can have an unhealthy impact on body weight. On the other hand, health-promoting environments, such as walkable neighborhood streets, in conjunction with physically active residents, can have a positive impact on body weight over time." said Dr. Li.

The study is part of the Portland Oregon Neighborhood Environment and Health Study where researchers are following a sample of over 1200 local residents ages 50-75 years old over a three-year period using anthropometric and survey measures, such as body weight, height, eating habits, food intake, physical activity, and perceptions of their immediate neighborhood environment. Researchers have also taken objective measures of built environment characteristics, such as land-use mix, density of fast-food outlets, street connectivity, & public transit stations, and the presence of green & open spaces in 120 randomly selected neighborhoods in Portland, Oregon. The overall objective of the research project is to examine change in body weight and physical activity in relation to built environment.

"To combat the obesity/overweight problem, it appears clear that, from the perspectives of public health and urban design, efforts are needed to improve features of modifiable built environments by making them more conducive to healthy eating and increasing physical activity," noted Li.