The battle against childhood obesity appears to begin at an early age.  A new study finds a weight problem can begin for a child as early as 5 years old.

"So, what they're saying is that the problem time is really those kids that are overweight or at the higher end of their BMI percentiles. When they're 4 and 5, those are the kids that when they are in 8th grade are obese," explained Dr. Sara Lappe, who did not take part in the study but is a pediatrician at Cleveland Clinic Children's.

Emory University researchers looked at the incidence of childhood obesity among more than 7,700 children ages 5 to 14.  They found when children entered kindergarten at 5 years old, 12% were obese and another 15% were overweight.

Although the annual incidence of obesity dropped between kindergarten and 8th grade, results show overweight 5-year-olds were four times as likely as normal-weight children to become obese.

Among children who became obese between the ages of 5 and 14, nearly half had been overweight and 75% had been above the 70th percentile for body-mass index when the study began.

Researchers say parents should pay close attention to their child's weight, even when they're very young.  Lappe says what you think is "baby fat" should not be ignored.

"A lot of people think that those kids that are overweight at 4 or 5 just have baby fat and that they'll get taller and grow out of it, but this study is telling us that that is not going to happen. That they have a high risk of being obese when they're older," explained Lappe.

Complete findings for this study are in the New England Journal of Medicine.