• One of the ways to qualify for surgery is to have a Body Mass Index (BMI) greater than or equal to 40.
  • If you have a slightly lower BMI, but you also have another obesity-related condition – such as type 2 diabetes, heart disease, or sleep apnea – you may also qualify.

Doctors may recommend bariatric surgery to help people with obesity shed pounds and keep them off. But in order to get it, you should already have tried unsuccessfully to lose weight through other means, says Fatima Cody Stanford, MD, an obesity medicine physician at Massachusetts General Hospital’s weight center.

Someone should first try altering their lifestyle by doing things like getting more exercise or improving their diet, she says. “If you have done those things and maybe even tried medication for weight loss but you still have moderate to severe obesity, I would strongly consider metabolic and bariatric surgery.”

Bariatric surgery requirements

According to Stanford, three types of people would be eligible for surgery:

  1. Someone with severe obesity, meaning they have a Body Mass Index (BMI), a ratio of weight to height, greater than or equal to 40.
  2. Someone with moderate obesity, defined as a BMI between 35 to 39.9, who also has a serious obesity-related condition, such as type 2 diabetes, heart disease, or obstructive sleep apnea.
  3. Someone with a BMI below 35 may also qualify, if they have type 2 diabetes that isn’t responding to typical treatments, like medications. “Often sending them to surgery is the tool we need to shift their blood sugar control,” Stanford says. Diabetes will resolve in 80% of patients within two days of surgery, she says.

The American Society of Metabolic and Bariatric Surgery (ASMBS) estimates that 252,000 bariatric surgeries were performed in the US in 2018. But the need is much greater, according to Stanford. “Only one percent of the patient population that meets the criteria for surgery does get that surgery,” she says.

No age limit on who qualifies for bariatric surgery

The American Academy of Pediatrics (AAP) says that substantial evidence suggests that surgery is the most effective weight loss option for many young people with severe obesity. The AAP does not set an age at which children are too young for bariatric surgery, saying instead that the decision should be made by children and their families.

Stanford says she has seen the benefits to her patients who had bariatric surgery as children and have since grown up. Likewise, a study published in the New England Journal of Medicine in 2019 followed 161 adolescents for five years after they had bariatric surgery. The researchers found they lost significant amounts of weight. Compared to adults in the study, the adolescents had more improvement in diabetes and high blood pressure, but also more follow-up operations.

"I also believe if you happen to be in your late 60s, early 70s and have always struggled with your weight this might be considered an option," she says. "We really should be considering it across the age spectrum."

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