The study results were presented at the Pediatric Academic Sciences meeting in Seattle.
Plain and simple, kids are drinking too much fruit juice and whole milk and getting too much fat in their diet, says Cynthia Sass, RD, a nutritionist with the BayCare Healthy System in Clearwater, Fla., and a spokeswoman for the American Dietetic Association. She agreed to comment on the new findings.
"Fruit juice does have nutrients, but if children aren't exercising to burn off those calories, they just contribute to weight gain," she tells WebMD. "With milk, I think there might be some confusion. After age 2, children don't need whole milk. Low-fat milk has the same amount of calcium and protein -- just less fat."
In 1999, the ADA released a food pyramid specifically for children: 6 servings from the grain group, 2 from fruits, 3 from vegetables, 2 from milk, 2 from meat, and "less" fats. If children are drinking fruit juice plus eating fruit -- and who knows what else -- those extra calories become fat, she says.
The impact of obesity on children's overall lives is at stake. "Childhood obesity not only affects a child's self-esteem, it also is associated with multiple medical consequences," says lead researcher Teresa Quattrin, MD, professor of pediatrics at the State University of New York at Buffalo, in a news release.
"In fact, the incidence of type 2 diabetes in children has risen significantly in recent years, along with high prevalence of obesity," she says. "Children at risk of obesity must be identified very early, even at the preschool level."
A recent survey from the National Center for Health Statistics shows that from 1999 to 2000, 15% of children between the ages of 12-19 were overweight and 15% between the ages of 6-11 were overweight.
Childhood obesity is rising at an alarming rate, researchers say. Compared with children of normal weight, overweight children are much more likely to become overweight adults -- with all the health problems linked with adult obesity, such as diabetes and heart disease.
Quattrin's study analyzed data on 385 children between ages 2 and 6, looking for signs of obesity, diabetes, and high cholesterol. All children were being referred to a specialist because they were overweight.
At the initial visit, the child's parent or guardian was counseled on dietary and activity changes that would help the child lose weight.
Two years later, researchers again collected data on the children, finding that the children had all put on more weight despite the counseling their parents received. The children's body mass index (BMI) had increased on average from 29 to 32. In children, a BMI over 26 is considered overweight.
In fact, 86% of 177 children were obese before the age of 6, and children were obese for an average of three years before they were referred to a weight-loss specialist, reports Quattrin.
Children as young as age 4 had abnormally high insulin levels, she says, a risk factor for diabetes. In addition, 13% of 147 children who had cholesterol levels checked showed high cholesterol levels, a sign of liver function problems.
Clearly, educating parents and guardians did not make a difference in the children's obesity problem -- yet it's very important, researchers say. Parents and the school system have the most impact on tackling kids' obesity problem, they add.
It's true -- parents have the most impact on what their kids eat, more than sports celebrities or other kids, Sass says.
"Parents have a fundamental role to teach their child healthy habits at home," Sass tells WebMD. "If the family as a whole is trying to consume more vegetables, it's going to impact how small children eat."
Schools should let kids keep healthy snacks in their backpacks, she adds. "When a child needs to eat is more closely tied to physical activity. If they're eating more than they need, they will put on weight. If they're eating less than they need, they obviously are going to be fatigued and irritable. Parents help children learn how nutrition and physical activity go hand in hand."
Even though obesity can have a genetic component, other factors play important roles -- food available at home and school, watching too much TV, playing computer games, and not getting enough exercise, researchers add. Also, parents need to be better role models.