A new national study has found modest declines in obesity among 2- to 4-year-olds from poor families, a dip that researchers say may indicate that the obesity epidemic has passed its peak among this group.
The study, by researchers from the Centers for Disease Control and Prevention, drew on the height and weight measurements of 27 million children who were part of the federal Women, Infants and Children program, which provides food subsidies to low-income mothers and their children up to the age of 5.
The study was based on data from 30 states and the District of Columbia and covered the years from 1998 to 2010. The share of children who were obese declined to 14.9 percent in 2010, down from 15.2 percent in 2003, after rising between 1998 and 2003. Extreme obesity also declined, dropping to 2.07 percent in 2010 from 2.22 percent in 2003. The study was published Tuesday in The Journal of the American Medical Association.
The report defined a 3-year-old boy of average height, almost 3 feet 2 inches tall, as being obese when he weighed 37 pounds or more. The same boy was categorized as being extremely obese when he weighed 44 pounds or more.
“The declines we’re presenting here are pretty modest, but it is a change in direction,” said Heidi M. Blanck, one of the study’s authors and the acting director of the Division of Nutrition, Physical Activity and Obesity at the disease centers. “We were going up before. And this data shows we’re going down. For us, that’s pretty exciting.”
The findings were another sign that one of the nation’s seemingly intractable health problems may be reversing course, at least among children. Single interventions like school exercise programs have not worked, and public health experts now say that only a broad set of policy measures has a chance of success.
Over the past year, several major cities, including Los Angeles, New York and Philadelphia, have reported obesity declines among some parts of their student populations.
The new study was one of the first to document a national decline in obesity among young children from low-income families. Researchers say that is particularly meaningful in a population that is disproportionately at risk. Twenty percent of poor children are obese, compared with about 12 percent of children from more affluent families, according to the centers.
It is unclear what drove the decline, but Dr. Blanck offered hypotheses. Breast-feeding, which often leads to healthier weight gain for young children, has increased since 2000. The percentage of 6-month-olds still being breast-fed increased to 47.7 percent among children born in 2009, up from 34.2 percent among children born in 2000.
Breast-feeding of infants from low-income families has risen over the years. In 1980, only 28 percent of infants from those families had ever been breast-fed, compared with 66 percent in 2011.
Dr. Blanck also pointed to changes in the environment, like those documented in a report about food marketing practices released by the Federal Trade Commission on Friday.
The agency found that the amount of money spent on food marketing to children declined by nearly 20 percent from 2006 to 2009, with the biggest drop in television advertising. The total spent on food advertising to youths in 2009 was $1.79 billion, the report said.
The report, based on data from 48 major food and beverage marketers, also found that cereals marketed to children ages 2 to 11 had about a gram less sugar per serving in 2009 than in 2006 and slightly more whole grain.
Marketing to children of the most sugary cereals — those with 13 grams or more sugar per serving — was virtually eliminated between 2006 and 2009, according to the report.
But drinks marketed to children still averaged more than 20 grams of added sugar per serving, the report found. Most of the improvements in beverages in the time period were in those sold in schools, the report said.
Dr. Blanck said she was hopeful that several national programs begun in the past few years would help extend the early declines. One initiative, Let’s Move! Child Care, initiated by Michelle Obama’s office, helps child care centers serve healthier food and include physical activity throughout day.
Changes in the foods that are subsidized in the Women, Infants and Children program, like less financing for fruit juice and more for fruits and vegetables, may also help, she said.
