May 29 (HealthDay News) -- U.S. researchers are launching an observational study to evaluate the risks and benefits of bariatric weight-loss surgery in teens.

Bariatric surgery is meant to help people lose weight by shrinking the size of their stomach in order to reduce their intake of food and calories. The Teen Longitudinal Assessment of Bariatric Surgery (LABS) study, conducted by a team at the U.S. National Institutes of Health (NIH), will examine whether this is an appropriate treatment option for overweight teens.

Over the next five years, the study will enroll 200 teens scheduled for bariatric surgery and compare them to 200 adult bariatric surgery patients who've been obese since they were teens. All the participants will be followed for two years after the surgery.

Teens ages 14-19 are eligible for the study, but researchers may allow younger patients to enroll if they meet the criteria.

"The reasons for weight gain are complex and multifactorial, influenced by genetics, environment, eating and physical activity habits, and society. The information gathered from Teen-LABS will help determine if adolescence is the best time to intervene with this surgical therapy," Dr. Thomas Inge, chair, Teen-LABS and principal investigator for the Data Coordinating Center and Clinical Center at Cincinnati Children's Hospital Medical Center, said in a prepared statement.

Almost 17 percent of young people ages 6-19 in the United States are overweight, according to recent statistics.