Chubbiness in babies may be a sign of good health, but it may also be a warning sign of obesity in early childhood.

In a newly published study, babies who weighed the most at the age of 9 months tended to be among the heaviest when they reached age 2.

The study is among the first to track the weight of a nationally representative sample of very young children; researchers say it suggests that even babies are not exempt from the obesity epidemic.

"We are certainly not saying that overweight babies are doomed to be obese adults," study researcher Brian Moss, PhD, of Detroit's Wayne State University tells WebMD. "But we did find some evidence that being overweight at 9 months of age is a predictor of being overweight or obese later in childhood."
Heavy Baby, Heavy Kid?

Since there is no accepted measure of obesity in very young children, Moss and colleagues considered kids in the study to be at risk for becoming obese if their weight was in the 85th to 95th percentile on standard growth charts.

For the purposes of the study, babies and 2-year-olds whose weight was above the 95th percentile were considered obese.

Using data from the Early Childhood Longitudinal Study-Birth Cohort, the researchers tracked the weight of around 7,500 children at age 9 months and 2 years. The children were born in 2001.

They concluded that around 32% of the children were either at risk for becoming obese or were obese at the age of 9 months and 34% were at risk or obese by the age of 2.

Children who were considered obese at the age of 9 months had the highest risk for being obese at age 2.

Forty-four percent of babies who met the study's definition of obese remained obese at age 2. The overall percentage of children considered obese increased from 17% at 9 months to 20% at age 2.

Hispanic children and children living in low-income families had the highest risk for obesity at both time points. At age 2, 40% of children living in the lowest income homes were obese or at risk for obesity, compared to 27% of children living in the highest income homes.

And 40% of Hispanic children were obese or at risk, compared to 31% of whites and 35% of blacks.

The study appears in the January-February 2011 issue of the American Journal of Health Promotion.
Expert: 'Keep Junk Food Out of Diet'

While baby fat may prove to be a predictor of being overweight in childhood, no one is suggesting putting babies on diets.

Childhood obesity expert Joyce Lee, MD, of the University of Michigan at Ann Arbor, says babies who are exclusively breastfed or bottle-fed should never be denied the breast or bottle.

Once solid foods are introduced, however, Lee says parents can and should make healthy choices for their children.

"These days, children are introduced to junk food at earlier and earlier ages," she says. "I know of 9-month-olds who eat French fries. "

She says keeping junk foods out of young children's diets and including lots of fruits and vegetables can have a big impact on a young child's weight.

Lee is an assistant professor in pediatric endocrinology and health services research at the University of Michigan.

"You can't tell a 9-month-old or a 2-year-old to eat right and exercise more, but you can make healthy choices for them," she says.