Linking fast food proximity to obesity

California's nearly 3 million 9th graders are at least 5.2 percent more likely to be obese if there is a fast food restaurant within a tenth of a mile of their school, according to a new study by University of California, Berkeley, economists who calculated that these students eat 30 to 100 more calories per school day than their non-obese counterparts. But they found no connection between fast food and obesity if the outlets are a quarter-mile to half a mile from high schools, and no correlation between obesity and the presence of non-fast-food restaurants near a school, indicating their findings reflect more than simple increases in local demand for restaurants in general. Their accompanying analysis of weight gain by pregnant mothers and their proximity to fast food outlets showed a much smaller impact for the moms than for the students. "Our results imply that policies restricting access to fast food near schools could have significant effects on obesity among school children, but similar policies restricting the availability of fast food in residential areas are unlikely to have large effects on adults," their report concluded, noting that transportation limits on youths may be a factor. Obesity among children ages 6-19 in the United States increased from about 5 percent in the early 1970s to a whopping16 percent in 1999-2002, and the number of fast food restaurants doubled in the same period. Economists Stefano DellaVigna and Enrico Moretti of UC Berkeley, economist Janet Currie of Columbia University and economist Vikram Pathania, who recently earned his Ph.D.