Schools should be more aggressive in teaching children about heart disease (search) and the risks of bad diet and little exercise, the American Heart Association (search) said Monday.

The call for bolder action in schools follows the Institute of Medicine's (search) recommendations last month calling for a wide-ranging attack on childhood obesity by involving parents, schools, communities and the government.

Estimates are that more than 15 percent of American children are very overweight, or obese.

Laura Hayman, a nurse and professor who wrote the heart association statement, said national data show about 80 percent of children aren't getting the recommended five or more servings of fruits and vegetables each day. She also said that 44 percent of high school students aren't in physical education classes.

"Through schools, hopefully you can reach the children, teachers and parents," said Hayman, who teaches at New York University and Lenox Hill Heart and Vascular Institute of New York.

Experts agree that the schools are a good place to start.

Judith Young, of the Virginia-based nonprofit American Alliance for Health, Physical Education, Recreation and Dance, said educating kids on the issue is critical. "If we don't teach them how to keep themselves healthy, then all the other things kind of don't matter."

The heart association statement, published in the journal Circulation, calls for more phys ed classes, heart-healthy meals and a tobacco-free environment from preschools through 12th grade and during after-school programs.

Dr. Catherine L. Webb, a professor of pediatrics at Northwestern University's Feinberg School of Medicine in Chicago, points out that families are often collectively obese.

"When a child starts to bring home knowledge, then the family I think will jump on the bandwagon," said Webb, who works on a heart association council focusing on cardiovascular disease among young people

Obesity is linked to diabetes, high blood pressure, high cholesterol and other problems, and it's a risk factor for cardiovascular disease, Hayman said.

The heart association recommendations call for teaching kids the major risk factors for cardiovascular disease and ways to avoid it.

The group also recommends that physical education be required at least three times a week from kindergarten through 12th grade -- with 150 minutes in school each week for elementary students and at least 225 minutes per week for middle school students.

According to the recommendations, school meals should meet heart-healthy guidelines.

Texas Agriculture Commissioner Susan Combs, who issued a school nutrition policy that took effect this year restricting fried and fatty servings and setting other food rules, said that school administrators understand the importance of physical education and nutrition, but they are dealing with limited resources.

More health education, for instance, might cost money for printed materials.

"A lot of [schools] are saying we'd love to do it, but give us the resources," Combs said.