Warning that the path to obesity can start during toddler-hood, pediatric experts say parents should make sure 3- and 4-year-olds get an hour of active play each day along with five fruits and vegetables.
"We think that may be a vulnerable period to start excess weight gain," said Dr. Stephen R. Daniels, professor of pediatrics and environmental health at Cincinnati Children's Hospital Medical Center.
Daniels was the lead author of a statement published Monday in the American Heart Association journal Circulation, which devoted the issue to the topic of obesity.
Toddler-hood is "also a time when dietary patterns may become more like those of adults, and also when many children develop physical activity patterns both good and bad," he wrote in an e-mail message.
Childhood obesity has become such a threat to public health that it could reverse the last half-century's gains in reducing cardiovascular disease and death, the heart association said.
Dr. Reginald Washington, a pediatric cardiologist in Denver who co-chairs the task force on obesity for the American Academy of Pediatrics, said that doctors still need to be educated about monitoring children that young for signs of obesity.
"Those of us that have been looking at this problem believe that prevention is better than treatment," Washington said. "Once you become obese it's very difficult to lose that weight and keep it off. If you are in the habit of not eating large portions, if you are in the habit of being physically active, that's going to stay with you."
Toddlers should eat five fruits and vegetables a day along with fiber-rich grains and should switch from drinking full-fat dairy to 1 percent or fat-free dairy products after age 2, according to the heart association. They should have an hour of "active play" each day and limited time not being active, the statement says.
The prevalence of overweight children and adolescents has almost quadrupled from less than 5 percent in the 1980s to about 16 percent today. An overweight child is at increased risk for problems including diabetes, high blood pressure, sleep apnea and high cholesterol.
Even so, Dr. Priscilla Hollander, head of endocrinology at Baylor University Medical Center in Dallas, said, "I think it may be a little shocking to say we do have to do this for toddlers."
Carina Terry, 39, who lives in the Dallas suburb of Allen, has been trying to establish healthy habits among her four children, ages 2, 4, 5 and 7.
Terry, who home-schools her children, has a food pyramid posted in front of the kitchen table. "It really helped them to understand what food we need to eat and why," said Terry, whose children do not have any weight problems.
She is also making sure that they get enough exercise. "We ride our bikes to the park, have a picnic and play," she said.
"They are becoming accustomed to a variety of foods and also an active lifestyle," she said. "Those habits that develop early will live with them forever."