SAN FRANCISCO (The New York Times News Service) -- Eight months ago, Taeylor Barker ate whatever she wanted, whenever she wanted, and she never got any exercise.

Only 13 , she was already carrying more than 300 pounds on her 6-foot frame, but when her pediatrician suggested she join Healthy Hearts, a weight-loss program for teens at Oakland Children's Hospital, Taeylor balked. She was shy and scared of facing other people -- doctors, nurses, nutritionists, even other overweight teens.

"But I wanted to lose the weight, so I decided it didn't matter who was there," Taeylor said. "Within a month I could feel the difference. My clothes were too big. I'm even losing weight off my feet."

Taeylor is down more than 18 pounds since November and she's already a major success story, even though she has another 100 pounds to go.

She is among an alarming number of teenagers in the United States who are overweight or obese -- and doctors and other weight-loss experts say they are facing what feels at times like an insurmountable battle to help these kids stay healthy.

"It's overwhelming. It's just a mountain of a problem," said Dr. Laura Bachrach , a pediatric endocrinologist at Packard Children's Hospital at Stanford, where she helped established a clinic for children with pre-diabetes last month.

In the United States, hundreds of programs like Healthy Hearts and the Stanford clinic have sprung up in recent years. They are designed to help obese teenagers whose weight is putting them at risk for chronic conditions, like heart disease and Type 2 diabetes that years ago were unheard of except in adults -- and older adults, at that.

These programs target what doctors consider an especially vulnerable, and difficult to treat, population. Often, their goal isn't even weight loss, but weight maintenance -- to help the kids stop gaining -- while doctors and patients attack some of the more problematic symptoms of chronic disease.

A study recently released by the American Academy of Pediatrics found that from 1999-2008, 34 percent of U.S. kids ages 12 to 19 were overweight or obese. In that same age group, 14 percent had hypertension or pre-hypertension, 22 percent had borderline or high cholesterol, and 15 percent had Type 2 diabetes or pre-diabetes.

While the rates of obesity and other risk factors like high blood pressure remained fairly stable over the 10-year period of the study, the rate of Type 2 diabetes increased significantly -- from 9 percent in 1999 to 23 percent in 2008.

"Unfortunately, the results weren't a surprise," said Dr. Lydia Tinajero-Deck , co-director of the Healthy Hearts program. "Our preteens and teens are sick."

Tinajero-Deck and other doctors who specialize in treating teenagers said it's clear why kids in this age group are at risk for gaining weight and developing the earliest signs of chronic disease.

Teens can be impulsive and a little reckless, and they don't always put much thought into the long-term consequences of everyday decisions -- from what they'll eat to whether they'll go for a walk or watch TV after school. Many of them don't get enough exercise, either in organized sports or P.E. classes at school.

And then there are the self-esteem issues. Almost every teenager goes through a period of faltering confidence, and a weight problem may only make matters worse. That's why many physicians said they talk to teens about improving their health, not losing weight.

"Success with weight management programs with teens -- it's been patchy," said Dr. Padmaja Padalkar , assistant chief of pediatrics at Kaiser San Jose Medical Center. "The best way to reach out to teens is to allow them to dictate what it is they can work on and what they can't. We try to set very, very small goals for these patients. Any small step is a step in the right direction."

That's a thought echoed by Padalkar's peers. Doctors and other health care providers agree that there are simply too many patients, and too few weight-loss programs that actually work, to make a big dent in the problem nationwide.

The emphasis, they say, needs to be twofold: to help individual teens get healthier, if not thinner, and encourage wider public health policies to improve the U.S. food and exercise climate.

"This is not a problem that doctors are going to solve," said Bachrach. "It's going to be a huge social effort to fix what's gone wrong in the past two generations."

Still, Bachrach said she's ready to tackle one patient at a time. "We accept small victories," she said with a laugh. "If someone loses five pounds, we jump up and down."

Most of the teen weight-loss programs involve entire families -- with the idea that kids are going to need all the support they can get -- and preach the basics of good nutrition and exercise.

In the Healthy Hearts program, patients and their families participate for six months, during which they have monthly doctor appointments, plus meetings with nutritionists and a variety of healthy and fitness experts. They can also join a teen fitness program at the Oakland YMCA -- kids who finish the program get a year of free membership to the gym -- and help with a community garden.

Taeylor Barker has learned to love the gym, and she's set up a small herb garden at the West Oakland home where she lives with her grandmother, Karen Slider. She goes to the YMCA two or three times a week -- sometimes taking water aerobics classes with Slider, sometimes working with a personal trainer, and almost always working out with a group of girls she met in a Teen Fit class.

"I want to lose 100 pounds," Taeylor said. "I know it's not impossible. I have to have confidence in myself that I can do it."  

Copyright 2012 The New York Times News Service. All rights reserved.