One of the topics now included in the updated ABOM test content outline is the built environment (A.8), specifically the relationship between the built environment and obesity. The built environment is the opposite of the natural environment and refers to everything that humans have constructed or modified. This includes large-scale features, such as cities, as well as granular elements, such as the availability of park benches, and downstream effects of these environments, such as pollution. The goal of the ABOM is to understand which characteristics of the built environment are associated with excess weight, identify contributors to the obesity epidemic, and develop better strategies to mitigate their effects.

From a bird’s-eye view, consider how the built environment influences population rates of excess weight by promoting or limiting physical activity. One key component is walkability. Studies have shown that neighborhoods with high walkability, characterized by adequate sidewalks, mixed-use zoning (where residential and commercial spaces coexist), and safer environments, are associated with lower rates of diabetes and elevated blood pressure. In contrast, urban sprawl, where residential areas expand farther from workplaces, schools, and places of worship (often due to zoning regulations), reduces the practicality of walking or cycling and promotes reliance on vehicle travel. Key elements that contribute to increased walkability include:

  • Density: Higher population density supports a greater concentration of jobs and services within a given area. Think of a densely populated city versus a more rural town.
  • Land use: Mixed-use zoning, where residential, commercial, and recreational areas are intermingled, reduces distances between destinations and promotes walkability.
  • Street network: Urban areas typically have shorter blocks and more connected street grids, decreasing distances between points and making walking more convenient than other forms of transportation. In contrast, less-populated areas often have curved streets or cul-de-sacs, which may lack sidewalks.

For example, let’s use New York City as an example. This highly dense city features mixed residential and commercial zoning, wide sidewalks, and barriers to personal vehicle use. Although subways are the predominant mode of transportation, which may seem to reduce walkability, the most common way to access them is by walking. In contrast, more sprawling towns often require automobiles for commuting and accessing shopping areas, resulting in lower walkability. There are, of course, important limitations and potential biases, such as whether healthier individuals are more likely to choose walkable neighborhoods, whether these areas offer more opportunities for physical activity, and the influence of socioeconomic factors on where people live. Overall, however, an inverse relationship is consistently observed: higher walkability is associated with lower rates of excess weight.

Incredibly, individuals living in highly walkable areas accumulate nearly 90 additional minutes of moderate-to-vigorous physical activity per week compared to those in the least activity-friendly neighborhoods, making them more likely to meet physical activity targets. These findings are associated with lower rates of obesity, as well as comorbidities such as diabetes, metabolic disease, and hypertension.

Note: In a prior blog, we covered food deserts and swamps, which are components of the food environment, so make sure to check that out here.

Let’s move on to air pollution. Numerous studies have identified air pollution as a risk factor for adverse metabolic outcomes, including diabetes and hypertension. In contrast, green spaces, such as parks and nature trails, are associated with lower levels of air pollution and increased physical activity. In fact, there is a correlation between the smaller sizes or absence of parks and the risk of excess weight, particularly in the pediatric population. In addition to physical benefits, green spaces have positive effects on mental health. While further research is needed to establish causality and minimize bias, current evidence suggests that increased access to spaces for physical activity is associated with improved overall health.

As the field of environmental epidemiology continues to grow alongside expanding longitudinal research, policy efforts at the local, state, and federal levels may increasingly focus on improving opportunities for physical activity and reducing cardiometabolic risk. The built environment, including access to parks, safe walking paths, and the availability of grocery stores versus fast-food outlets, directly influences physical activity and dietary behaviors. In contrast, higher levels of air pollution, reduced walkability, and limited or smaller park spaces are associated with excess weight. Familiarity with these associations will help you navigate built environment questions on test day.

Sample Question

A city implements policies to improve public health by modifying the built environment. Which of the following interventions is most likely to reduce obesity prevalence?

A. Increasing highway access
B. Expanding parking infrastructure
C. Increasing mixed-use zoning
D. Reducing access to public transportation

Next Week: Tirzepatide Studies/Trials

Upcoming: Monthly Knowledge Check: This consists of a checklist of objectives and questions based on the prior month’s blog posts. In addition, brief explanations of the sample questions will also be included.

For more practice questions, check out the following:

  • Obesity Medicine Board Review Questions (2026)
  • Obesity Medicine Practice Tests (2026)

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