Households with children are cutting the junk food

American families with children bought 101 fewer calories per person per day in packaged foods in 2012 than they did in 2007, according to an analysis of a pledge by big food companies to reduce calories in the marketplace. It's an "impressive" accomplishment but not sufficient to reverse childhood obesity, experts say.

The assessments, published Wednesday in the American Journal of Preventive Medicine, follow on an earlier report on the work of the Healthy Weight Commitment Foundation - 16 big food companies that agreed to reduce by 1.5 trillion the total calories they sold by 2015.

That mark has been exceeded significantly: The companies - which together account for about a third of all the calories in the marketplace - reduced calories sold from 2007 through 2012 by an average of 78 per person, or 6.4 trillion total.

That is an impressive accomplishment but won't reverse the epidemic of childhood obesity, especially among poor people and some minority groups, according to independent evaluations of the project conducted by scientists funded by the Robert Wood Johnson Foundation.

"There has been a cultural shift in this country - especially households with kids have really started buying fewer calories," Barry Popkin, a professor in the School of Public Health at the University of North Carolina, said Monday by phone. Popkin and Shu Wen Ng, also of the University of North Carolina, wrote the evaluation of what people bought, using Nielsen Homescan data of more than 61,000 households; they and Meghan Slining evaluated what was sold.

The 16 companies, which include ConAgra Foods, General Mills, Kellogg, Kraft Foods, and Cola-Cola, are selling more lower-calorie versions of popular products. But that doesn't mean they're healthful, several experts said.

"What we don't have is an increase in beans, whole grains, produce" - change that might come if those foods became cheaper relative to packaged products, Popkin said.