A recent study out of the School of Medicine found that family members of gastric bypass surgery patients also experienced weight loss and improved healthy behavior usually associated with bariatric surgery.

The study, published in this month’s Archives of Surgery, examined 35 gastric bypass surgery patients and their family members, both adults and children, one year after surgery to see if those family members had experienced weight loss along with the bariatric patients.

Twelve months after the operation, obese adult family members experienced significant weight loss. Researchers also observed that obese child family members had a lower body mass index than expected for their growth curve.

“There were also a bunch of other healthy behaviors: less alcohol consumption, less TV watching, more physical activity and better controlled eating,” said medical school director of bariatric surgery and study author John Morton.

Adult family members made significant changes in a number of behavioral areas. They engaged in less emotional and uncontrollable eating and higher activity levels. Regardless of weight, they also decreased their monthly alcohol intake from 11.4 to 0.8 drinks per month.

Morton said he was not surprised by the results, stating that most of his gastric bypass surgery patients had family members who reported weight loss at check-ins before the study.

“There was a paper in the New York Journal of Medicine and it showed that when you have an obese family member or an obese spouse it increases your risk of becoming obese yourself,” Morton said. “They call it a social contagion. So I put both of those things together and asked if the opposite could occur, where you see patients who lose weight and pass on good habits to their family members.”

The study helped to highlight the familial nature of obesity.

“I think one thing that I came away with from it is that obesity is really a family disease,” he said. “When one family member has it there is a risk of someone else having it. If you treat one family member you should probably treat all of the family members.”

Morton said he plans to follow up with these patients for their three-year anniversaries to ensure that the results have endured. He also said that they hope to extend the program to everyone in the bariatric surgery program.

“We have a clinic called the Bariatric and Metabolic Interdisciplinary (BMI) Clinic,” he said. “We will obviously extend all of the counseling that we do to the patients and to their entire family routinely. Beyond the Stanford BMI clinic, we hope to see all of the different bariatric surgery centers around the country embrace this.”

Today, 26 percent of American adults and 15 percent of children are considered obese. Stanford surgeons perform about 300 bariatric surgeries every year and there are more than 200,000 surgeries performed annually throughout the country. Morton said that he hopes that treating the families of bariatric surgery patients will create a ripple effect and spread healthy behaviors.