Where we live may influence how much we weigh even more than previously thought.

Where you live may influence how much you weigh even more than we previously thought, according to new research.

It’s long been known that the neighborhood a person lives in can impact their health status, including how much they weigh; evidence suggests that socioeconomic environments influence a person’s ability to adopt healthy behaviors. Now, a new study finds that moving between neighborhoods can also cause changes in body weight.

The research, published in the American Journal of Preventive Medicine, analyzed a sample of more than 1,000 Dallas County residents between the ages of 18 and 65 who researchers had followed for seven years. The study found that people who moved to poorer neighborhoods gained more weight than those who either stayed put or moved to a better or similar neighborhood.

To reach these findings, the residents were surveyed about their impressions of their neighborhoods. The neighborhoods were also rated based on a Neighborhood Deprivation Index (NDI) to determine socioeconomic status; a higher index indicates a more deprived neighborhood. Among the people in the study, 263 people moved to a neighborhood with a higher index, 586 moved to a lower-index neighborhood and 47 people moved to a neighborhood that had the same rating. Everyone else stayed in their same neighborhood.

The people who moved to the higher-index neighborhoods—the ones more deprived of resources—gained more weight compared to the people who either stayed put or moved to a neighborhood that had the same or lower index, even after controlling for variables like age, income, and physical activity. For every 1-unit increase in the neighborhood deprivation index, residents gained about 1.41 pounds. Notably, this neighborhood effect was cumulative: Of the people who moved to a more deprived neighborhood, the longer they stayed there, the larger the impact on their weight.

While it’s been known for some time that the socioeconomic characteristics of a neighborhood can predict trends in health, including body weight, this study is among the only sustained, naturalistic inquiries into the connection between weight and poor home environment, and the first to find a specific effect from the length of residence. More research is needed before the study authors can definitively explain the link, but they pointed to several factors as potential explanations.

The makeup of a more deprived neighborhood can encourage consumption of unhealthy foods or make it hard to stay fit, the researchers say. For example, research shows that poorer neighborhoods tend to have fewer full-service grocery stores but more convenience stores and fast-food restaurants, leaving residents with few options for fresh, healthy and affordable food; at the same time, concerns about neighborhood safety alongside physical barriers, such as traffic and polluted air, discourage residents from participating in outdoor physical activity. Together, these factors (and more) contribute to what experts call an “obesogenic environment” — one that promotes obesity.

Research has also linked changes in stress hormones to living in disadvantaged neighborhoods; in turn, these stress-induced changes increase obesity risk. through a variety of different mechanisms. Stress may lead to weight gain through stress-induced hormonal-, metabolic- and neurobiological changes as well as unhealthy eating behaviors. Additionally, stress — particularly chronic stress — may trigger anxiety and depression, which are both associated with child and adult obesity.

According to the National Institutes of Health (NIH), living environments can encourage obesity and make it difficult to maintain a healthy lifestyle; a lack of sidewalks and safe parks, an excess of fast-food restaurants with little access to fruits and vegetables, heavy food advertising and long work hours of residents all contribute. In contrast, prior research has shown that kids who live in places where they can walk to school or recreational facilities are significantly less likely to be obese. And a 2011 study found that families who moved to less-impoverished neighborhoods had lower levels of obesity and diabetes compared to families who stayed in their original neighborhood.

The new study underlines the strong ties between the built environment and the health of the residents who live in it. The findings also demonstrate how neighborhood disadvantage can be a source of socioeconomic disparities in health, highlighting a potential avenue for intervention.  “Addressing neighborhood deprivation as a risk factor for obesity and obesity-related cardiovascular disease requires consideration of public policy that can address sources of deprivation,” the study authors conclude.