Some doctors call it "the other f-word" — a problem they see every day but that many are reluctant to address: kids who are fat.

The issue is not new. But experts say it has acquired greater urgency as obesity has ballooned in the past 25 years, accompanied by sharp increases in diabetes, hypertension and high cholesterol, conditions that used to be largely the province of those middle-aged or older. In 1980, according to the federal Centers for Disease Control and Prevention, 7 percent of children were overweight; today the figures hover around 19 percent.

So why should doctors be reluctant to mention an obvious problem?

The reasons are many, experts say: fear of alienating a family or hurting a child; uncertainty about what weight-loss approaches have the best outcomes — or work at all; accelerating time pressures coupled with the requirement that doctors cover an increasing number of topics in a visit; and an insurance system that often does not reimburse doctors for follow-up visits to treat obesity alone. Many pediatricians also say they have no place to refer children who need more intensive help managing their weight.

Even the terminology used to describe children's weight problems is prompting debate as doctors draw up new guidelines for the diagnosis and treatment of obesity under the aegis of the American Medical Association and the American Academy of Pediatrics.

For several, years the CDC has recommended that clinicians classify children who are overweight — above the 85th percentile on growth charts that track height, weight and age — as at "risk of overweight." Those above the 95th percentile are called overweight — rather than obese — to avoid hurting their feelings.

Reginald Washington, a pediatric cardiologist in Denver who is co-chairman of the American Academy of Pediatrics' task force on obesity, said the CDC's "warm and fuzzy" labels obscure the health crisis.

"I think until people realize they have to change, they won't," Washington said, adding that one reason childhood obesity "is so out of control is that no one wants to talk about it."

Washington said he has been accused by parents of callousness or an inability to understand the problem when he tells them their children need to lose weight — criticisms he rejects.

Many parents, he added, are overweight themselves and are unwilling to make changes to help their children lose weight.

"There's a lot of denial," Washington said, adding that parents have told him they can't buy healthier foods because their children refuse to eat them, or they don't want to remove the TV set from a child's bedroom because he or she will get into trouble doing other things.

But other experts say that labeling kids overweight and obese may prove more harmful by making them feel there is little they can change. It is easy, they warn, to oversimplify a complex problem that may involve cultural differences, poverty and psychological factors.

"The issue is not as simple as telling people to eat more fresh fruits and vegetables and move more," said adolescent medicine specialist Adekemi Oguntala, who co-directs an obesity treatment program at Children's Hospital and Research Center in Oakland, Calif.

In some cases, she said, families don't have access to fresh produce, are resistant to making changes that involve the entire family, or eat cheap, high-calorie foods because they are accessible or affordable.

And, Oguntala said, even someone who is highly motivated and has struggled with weight knows how difficult the problem can be.

A recent study of 194 Latina mothers in California, presented at the Pediatric Academic Societies' annual meeting, found that 44 percent had children who were overweight by age 3, but three-quarters thought their children were of normal weight.

Sometimes ignorance is a factor. "People are not that knowledgeable," said Kelly Sinclair, a clinical nutritionist at Children's National Medical Center in Washington, D.C., where 38 percent of patients are obese. "They think their diet is healthy — that low-fat Pop Tarts are healthy or Goldfish crackers are because they're not potato chips. Some people count candy in the shape of fruit as a fruit."

Medical director of Children's general pediatric clinic Nathaniel Beers said he takes a straightforward approach with families whose children are overweight or obese. First he calculates a child's body mass index, then he asks parents and the child if "this is something they want to work on."

"Most people are willing to think about it," he said. Even those who haven't been successful controlling their own weight are often eager to help their child "because they don't want him or her going through what they've been through." It's important not to alienate parents by blaming them, he added.

"As pediatricians, we try to help get a dialogue going and to leave the door open," Beers said. Although he counts a few successes among his patients, Beers said "it's a huge uphill battle."