Children at the federally funded Head Start school in Woodbourne, New York, last year. The school provides early education, nutrition and health services to 311 children from birth up to 5 years from low-income families in Sullivan County, one of the poorest counties in the state of New York (Image: John Moore/Getty)

The great wave of obesity in US children may have crested. Children from low-income homes – who tend to be fatter than their counterparts from wealthier families – have become slightly, but significantly, leaner in recent years, a new government study reports.

Epidemiologist Ashleigh May at the US Centers for Disease Control in Atlanta, Georgia, and her colleagues used data from the Pediatric Nutrition Surveillance System, in which medical workers recorded the height and weight of about 11.6 million preschool children from 43 US states and territories who were enrolled in government nutrition-assistance programmes between 2008 and 2011. The researchers then adjusted the data to account for differences due to race, age and sex.

In 18 states and one territory, the proportion of children classified as obese declined significantly during the four years, they found. New Jersey, for example, which had one of the biggest changes, showed a drop from 17.9 per cent of children obese in 2008 to 16.6 per cent in 2011. In contrast, the obesity rate increased in only 3 states, with the others showing no significant change over time.


Tide turning

When the survey was run between 2003 and 2008 it showed an increase in obesity rate in 24 states and a decrease in only nine. “For the first time, we’re seeing a large number of states that are showing small but significant declines in childhood obesity,” says May. “Hopefully, we’re turning the tide.”

A few other studies over the past few years have hinted that rates of childhood obesity might be levelling off or even declining slightly in the US and around the world. However, May’s study provides the first proof that the decline extends even to the low-income children at greatest risk of obesity, says James Marks, senior vice-president for health at the Robert Wood Johnson Foundation, a health-focused philanthropic organisation based in Princeton, New Jersey.

The researchers cannot be certain about what is driving obesity rates downward. However, the US has made several important changes in health and nutrition policy in the past few years. Most notably, the government’s main nutrition-assistance programme for children now provides better access to fruits, vegetables and whole grains instead of high-fat dairy foods, and many childcare providers now give children more physical activity and less passive sitting.

“Clearly, the good news out of this study is that these interventions are beginning to pay some dividends,” says Richard Hamburg, deputy director of the Trust for America’s Health, a nonprofit disease-prevention organisation based in Washington DC.

Though May’s results are encouraging, Marks warns that it is far too early to say that the obesity problem is solved. “We have to treat these as fragile changes,” he says. “We’re still way too high in the proportion that are obese.”

Journal reference: Morbidity and Mortality Weekly Report, vol 62, p 629