David Ludwig, director of the obesity program at Children’s Hospital Boston, was against weight-loss surgery for kids, he says, because it ignored the real problem, a “toxic environment” jammed with junk food.

He’s since changed his mind.

The rate of obesity in children has tripled since 1980, according to the Centers for Disease Control and Prevention, boosting rates of sleep apnea, diabetes and heart disease. That’s why Ludwig, a leading childhood obesity researcher, says regulators should approve a procedure in which surgeons wrap a silicone band around children’s stomachs to help limit food intake.

A gastric band made by Allergan this year may become the first cleared by federal regulators to be sold to children as young as 14. For Allergan, the approval may open an avenue to as many as 2 million new customers, according to Christine Ren-Fielding, a surgeon at New York University’s Langone Weight Management Program. Both Ren-Fielding and Ludwig say use of gastric bands should be allowed for kids, with limits.

“Ultimately, we want to create a public health approach that makes surgery unnecessary — less junk food, better school lunch, physical education in school and after-school recreation activities,” said Ludwig, who is also a professor at Harvard Medical School in Boston, in a telephone interview. “But until we reach that time, surgery may be the necessary fallback for some of the most extreme cases.”

Ludwig said he has no financial ties to Allergan.

The bands are already implanted in some children, doctors say, and the latest data suggest adolescents lose 11 times more weight with the devices than with diet and exercise alone.

Food and Drug Administration approval would limit Allergan’s legal liability, said Ken Cacciatore, an analyst for Cowen & Co. in New York. It may also push insurers to help pay for the procedures, which can cost as much as $25,000, according to Allergan’s Web site.

Price is an issue for many obese teenagers, Harvard’s Ludwig said. “Low-income, minority populations tend to have greater chronic disease burden, and less ability to pay for the needed medical care,” he said. “Reimbursement is key.”

In 2009, 220,000 people in the United States underwent weight-loss surgery, according to the American Society for Metabolic and Bariatric Surgery, a Gainesville, Fla.-based organization of doctors who perform the procedures. That’s an increase from 28,800 in 1999, the group reported.

Surgery, though, should only be considered as a last resort for children, according to New York University’s Ren-Fielding, who said in a telephone interview that she’s already implanted gastric-band devices in some adolescents.

Edward Livingston, a surgeon at the University of Texas Southwestern Medical Center in Dallas, agreed. It’s important to be cautious because there’s no data available showing lap-bands are safe and effective longer term in either adults or children, according to Livingston, who said he has performed bariatric surgeries for 17 years in adults.

Harvard’s Ludwig believes a public health approach is important. After an ideal intervention, he said, no children would be candidates for bariatric surgery.

“We need a comprehensive national strategy to make this country healthier,” Ludwig said. “But for children who can’t manage their weight, especially when they develop a complication like Type 2 diabetes, then bariatric surgery may be the last resort that needs to be considered.”