Several years into a campaign to get kids to eat better and exercise more, child obesity rates have appeared to stabilize, and might be poised for a reversal.

But a study published Monday in the journal PNAS suggests that among adolescents, the【C1】_____signs are limited to those from better-educated, more【C2】__families. Among teens from poorer, less well-educated families, obesity has【C3】_____to rise.

That class-gap was not【C4】_____in younger children. But as children neared【C5】_____, the class differences became increasingly obvious.

【C6】_____between rich and poor in obesity rates are not new, and they are only one of many health gaps that make poor patients sicker and more likely to die【C7】__than richer ones. But if the public health message on obesity “has not diffused【C8】__across the population,” this gap could【C9】__efforts to stem a tidal wave of【C10】_____obesity-related diseases in the years ahead.

Researchers from Harvard University’s Kennedy School of Government found that【C11】_____activity may account largely for the【C12】_____trend in obesity between rich and poor.

If public health experts are to prevent childhood obesity and【C13】_____drive down future obesity among adults, they’ll have to figure out【C14】__less advantaged kids don’t get as much exercise, the authors of the latest study say. Yes, lack of【C15】__centers, playgrounds, and streets and sidewalks that【C16】_____walking, biking and playing are important, they wrote.

But, they added, “this is not the whole story.” Among children with parents who【C17】_____high on the socioeconomic scale, participation in high school sports and clubs has increased. But among their【C18】__from families of lower educational【C19】__and income, such participation has【C20】_____.

【C14】