African American and Hispanic adolescents whose schools are closer to fast-food spots are more overweight compared to Asians and Caucasian teens, according to a new study, highlighting the immediacy and availability of these eateries near children in the wake of the obesity epidemic.

Researchers published their findings in the current issue of Journal of Public Policy & Marketing, which found that having a fast-food restaurant a mile closer to school cancels out the benefits of exercising one day per week for all students. Results were even worse for Hispanic and black students in poor, urban neighborhoods; such proximity to a fast-food eatery cut out their benefits of exercising three days per week.

"Our study demonstrates that fast food near schools is an environmental influence that has magnified effects on some minority children at lower-income urban schools," said Brennan Davis, co-author of the study and assistant professor of marketing at Baylor University.

Davis and Grier took into account the income earnings of schools, body mass index (BMI), and soda consumption of students to put into perspective the restaurant's impacts.

They suspect that the teen's school environment is not under the parent's control in terms of food choices and that, during lunch or before and after school, students may linger into unhealthy eating habits.

"The findings imply that it is important to examine the behaviors and contexts associated with low-income and ethnic minority status in urban areas," said Sonya Grier, co-author and associate professor of marketing at American University. "These populations not only are the fastest growing but also have the highest rates of obesity, and research is relatively limited."

Researchers added that the public should be aware of marketing strategies as many ethnic populations are attracted to fast-food chains.

"As mobile geodemographic location targeting increases, fast-food promotions will likely target those adolescents nearest to fast-food outlets and who are at greatest risk for obesity," Davis said. "Voluntary industry actions, or policies that support healthier food near schools, can contribute to healthier school food environments."

Source: Grier S and Davis B. Are all proximity effects created equal? Fast food near schools and body weight among diverse adolescents. Journal of Public Policy & Marketing. 2013.