When Amanda Rodriguez was in high school, she was one of the few students who had a key to the school elevator. At 292 pounds, she couldn’t walk up the stairs.

“It was really embarrassing and it took a toll on my mental state,” said Amanda. “I was just really unhappy with myself.”

After both her parents had gastric bypass surgery and lost weight, they encouraged her to undergo the same procedure. Serafin Rodriguez was worried about her daughter’s health, especially when she showed early symptoms of diabetes.

Three years after her surgery, the results are dramatic.

Now 19, Amanda lost about 120 pounds. Last year she left home to study psychology at the University of Connecticut, and proudly describes how she can walk around the hilly campus.

“I thought I was going to be riding a bus constantly,” she said. “But now I’m able to go on school field trips and kind of interact with really cute guys, which is something that I did not think I was going to be able to do on a college campus all the way in Connecticut.”

Amanda’s case is part of a nationwide study of 890 adolescents who have had bariatric surgery. The study, released in March, followed up three, six and 12 months after surgery. The patients were between 11 and 19 and lost an average of 66 pounds. Sarah Messiah, Ph.D., one of the study authors at the University of Miami Miller School of Medicine, hopes the results will encourage more pediatricians to consider the procedure as an option for young people.

“To me you’re just kicking the can down the road while they get sicker as adults,” Messiah said. “For adolescents who do undergo the surgery, it’s the first time in their life that they feel really good. It’s like they have a second lease on life.”

There are three main kinds of bariatric surgery. Amanda and her parents had gastric bypass surgery, the most common procedure. This involves redirecting the small intestine to a stomach pouch that limits food intake. The average weight loss for these teens in the study was 107 pounds.

Patients who opted for the less invasive gastric banding lost an average of 44 pounds. In this procedure, an adjustable band is inserted around the stomach, like the thin part of an hourglass, to restrict the size of the stomach.

The third kind is a gastric sleeve, in which doctors remove a large portion of the patient’s stomach so that it takes the shape of a sleeve. None of the adolescents in the study had this procedure.

Obesity rates in the United States have doubled for adults and tripled for children between 1980 and 2008, according to the Centers for Disease Control and Prevention. Given this, medical professionals are looking at all options to help patients attain — and maintain — a more healthy weight.

Candidates for bariatric surgery are identified by body mass index (BMI) rather than weight. Patients with a BMI of 40 or higher qualify — an example would be a girl five-feet-five weighing about 250 pounds.

Dr. Mary Brandt, the director of the Adolescent Bariatric Surgery Program at Texas Children’s Hospital, says that younger candidates for this surgery should not be judged by the same criteria used for obese adults. For the benefits to be worth the “permanent and life-changing” effects of surgery, a teenager must exhibit serious health conditions such as diabetes, high cholesterol, fatty liver or hypertension.