The committee was set up as a response to a request from Congress to address the problem.

"The assumption is that people are overweight due to personal choices, but this isn't applicable to small children," said Leann Birch, professor of human development and family studies, and a member of the committee. "This is a problem for which families, communities and corporations must bear responsibility for changing social norms to promote healthy lifestyles."

Birch said that rather than assign blame to this growing epidemic, the Committee on Prevention of Obesity in Children and Youth looked at the problem as it currently stood to find recommendations that could improve it, and then issued a report that was released at a public briefing in Washington, D.C., on Sept. 30.

The report called for schools to implement nutritional standards for all foods served on school grounds and recommended that schools allow children to engage in at least 30 minutes of physical activity per day, among other recommendations.

Issues also addressed were the amount of time children and youth spend watching television, recommendations on altering meal portion sizes and steps parents can take to improve children's nutrition and activity levels.

"The committee's perspective is that [childhood obesity] is a very serious problem with serious health consequences," Birch said. "We need to start now, as soon as possible, to try to reduce the trends."

The main reason childhood obesity is such a problem is because it is tracking into adulthood, said George Graham, professor of kinesiology.

"If a child is overweight at age 4, he [or she] has a 20 percent chance of being obese or overweight as an adult, and overweight teenagers have an 80 percent chance, according to the American Academy of Pediatrics," Graham said. "We're trying to prevent children from being overweight so they won't become overweight adults."

The standards for obesity have to do with BMI (body mass index), which is a weight-to-height ratio. According to NIH, people with a BMI of 25 to 29.9 are considered overweight, and people who have a BMI of 30 or more are considered obese.

There are several factors that contribute to obesity in children, but at the most basic level, weight gain is caused by either increases in calorie intake, decreases in physical activity, or both, most experts say.

"I think our habits come from what parents introduce to us at home," Graham said. "If we start eating junk food as opposed to fruits and vegetables, we develop those habits and don't want to eat healthy food because it's not as enjoyable."

Sibylle Kranz, assistant professor of nutritional sciences, recently led a study of the changes in the diet of American preschoolers and found many are still consuming too much added sugar, specifically in fruit juice.

"A lot of children drink too much fruit juice, even though it should be limited to six ounces a day," Kranz said.

"In total amounts, childrens' average total caloric intake has increased about 200 calories in the past 21 years," she said. "This could explain the growth of childhood obesity."

Guy Le Masurier, assistant professor of kinesiology, said parents, schools and communities need to build environments that are conducive to physical activity.

"Nowadays, there is little purposeful physical activity, so people have to choose to be active," he said. "It needs to be enjoyable, or people won't do it. With children, we need to market it better."

Graham said that physically active children often have physically active parents.

"Parents need to find physical activities that their kids enjoy and feel successful at," he said. "Schools also need to have physical education programs that turn kids on to [types of exercise] they like just as much as playing video games."