Pitt Researchers Look At How Different Behaviors Affect Weight Gain After Gastric Bypass Surgery

Apr 9, 2019

A new study from University of Pittsburgh researchers looks at how different behaviors affect weight gain after gastric bypass surgery.

Gastric bypass is for people with severe obesity. It reduces the size of someone’s stomach and bypasses a part of the small intestine, thereby limiting both food intake and calorie absorption.

After the procedure, patients are put on a liquid diet, and as people return to a normal food they will gain back some weight. But if the number of pounds gained is substantial, the less likely someone is to benefit from this invasive surgery, and the more likely they are to have a resurgence of chronic conditions like diabetes.

In this eight-year study, which included more than 1,200 volunteers, researchers identified a number of behaviors that significantly and individually impact weight gain. These include spending several hours of leisure time in front of the TV or computer, not weighing one’s self weekly and binge eating.

“So, people have had episodes of not only loss of control but eating large quantities of food at once that had the biggest effect,” said epidemiologist Wendy King, the study’s lead author. “[But] that wasn't a very common behavior post surgery in part because it's actually difficult to binge eat when you've had your stomach reduced.

Because the researchers quantified the impact of each behavior, they showed these behaviors were independent from one another.

For example, if a patient ate one fast food meal a week, this resulted in gaining nearly half-a-percent back of the total weight they had initially lost. For every additional fast food meal, the impact grew. So, four meals caused someone, on average, to gain nearly 2 percent of the total weight they’d lost.

That means, in part, patients shouldn’t let perfect be the enemy of good. If someone makes an unhealthy choice at one point in their day or week, they still have many opportunities to make other decisions, which will result in less weight gain over time.

King said she would next like to study how sedentary, moderate and vigorous activity after bariatric surgery affects weight and health outcomes overtime.

The study was published in the journal “Annals of Surgery.”

WESA receives funding from the University of Pittsburgh.