LOS ANGELES (AP) ― New research sends a stark warning to overweight teens: If you develop diabetes, you’ll have a very tough time keeping it under control.

A major study, released Sunday, tested several ways to manage blood sugar in teens newly diagnosed with diabetes and found that nearly half of them failed within a few years and 1 in 5 suffered serious complications. The results spell trouble for a nation facing rising rates of “diabesity” - Type 2 diabetes brought on by obesity.

The federally funded study is the largest look yet at how to treat diabetes in teens. Earlier studies mostly have been in adults, and most diabetes drugs aren’t even approved for youths. The message is clear: Prevention is everything.

“Don’t get diabetes in the first place,” said Dr. Phil Zeitler of the University of Colorado Denver, one of the study leaders.

A third of American children and teens are overweight or obese. They are at higher risk of developing Type 2 diabetes, in which the body can’t make enough insulin or use what it does make to process sugar from food. Until the obesity epidemic, doctors rarely saw children with Type 2 diabetes. The more common kind of diabetes in children is Type 1, which used to be called juvenile diabetes.

Doctors usually start Type 2 treatment with metformin, a pill to lower blood sugar. If it still can’t be controlled, other drugs and daily insulin shots may be needed. The longer blood sugar runs rampant, the greater the risk of suffering vision loss, nerve damage, kidney failure, limb amputation - even heart attacks and strokes.

The goal of the study was simple: What’s the best way for teens to keep diabetes in check?

The study involved 699 overweight and obese teens recently diagnosed with diabetes. All had their blood sugar normalized with metformin, then were given one of three treatments to try to maintain that control: metformin alone, metformin plus diet and exercise counseling, or metformin plus a second drug, Avandia.

After nearly four years, half in the metformin group failed to maintain blood sugar control. The odds were a little better for the group that took two drugs but not much different for those in the lifestyle group.

Even so, Zeitler said doctors would not recommend this combination drug therapy because Avandia has been linked to higher risk of heart attacks in adults. Those risks became known after this study had started.

Another study leader from Children’s Hospital Los Angeles, Dr. Mitchell Geffner, agreed that Avandia can’t be recommended for teens, but said the study makes clear they will need more than metformin to control their disease.

“A single pill or single approach is not going to get the job done,” he said.

Among all the teens in the study, 1 in 5 had a serious complication such as very high blood sugar, usually landing them in the hospital.

The results were published online Sunday by the New England Journal of Medicine and presented at a pediatric meeting in Boston. The National Institutes of Health funded the study and drug companies donated the medications.

The “discouraging” results point to the need to create “a healthier `eat less, move more’” culture to help avoid obesity that contributes to diabetes, Dr. David Allen of the University of Wisconsin School of Medicine and Public Health wrote in an accompanying editorial.

Judith Garcia still struggles to manage her diabetes with metformin and insulin years after taking part in the study at Children’s Hospital Los Angeles. She has to remember to watch her diet and set aside time to exercise.

“Trust me, I’m working on it,” said the 19-year-old who lives in Commerce, Calif.

Kelsi Amer, a 14-year-old high school freshman from Patriot, Ind., knows how tough it is to keep her blood sugar from skyrocketing. Diagnosed at age 12, she takes metformin and gives herself insulin shots before school and at bedtime.

There are times when she has to miss class because she has to prick her finger to check her blood sugar or go with her mother to Cincinnati Children’s Hospital Medical Center for check-ups.

“I try real hard and all of a sudden, I’m back to high blood sugar” levels, said Kelsi, who was not part of the research.