How Gastric Bypass Changes the Brain’s Response to Food

Gastric bypass is one of the most common types of bariatric surgeries, also known as weight loss surgery. It is well known that this procedure creates a much smaller pocket where food is stored, to reduce how much the patient eats and results in weight loss. But thanks to a new study conducted by the Medical Research Council, it might go a little further than that. The study looks at how gastric bypass changes the brain, specifically its response to food. This response lowers hunger and the act of eating for pleasure. It is great news for gastric bypass patients who became obese due to an emotional connection with food.

The Study

This study was conducted with 61 patients, both men, and women. About 21 people in the study had lost weight from the gastric bypass procedure, 21 lost weight from the gastric band procedure, also known as a lap-band, and the remaining 20 patients were in a control group who did not have a weight loss procedure. All three groups consisted of patients within the same body mass index (BMI). Functional magnetic resonance imaging (fMRI) was used to look at brain activity. This is a scanning technique that measures brain activity and looks for any changes in the individual’s blood oxygen levels.

The Results

The results of this study showed that there were definite changes in the brain’s response to food in gastric bypass patients versus gastric band patients. Patients who had gastric bypass performed had less activity in their brain when they were showing images of food for this test. This group also had less appealing outcomes for the foods high in calories and based on a scale for this study, found high-calorie foods less pleasant if they were to eat them post-surgery. Additionally, gastric bypass patients tended to have healthier eating habits as a whole, opting for healthier options and skipping most high-fat or high-caloric foods. While gastric banding patients also eat healthier and less in quantity, they did show slightly elevated brain response to food, in comparison. As expected, the control group that didn’t have weight loss surgery had the highest amount of response and show traits like impulsiveness, mood alterations, and binge eating.

The reason behind these results was less clear, though the hormone changes in gastric bypass patients might have something to do with it. This group tended to have more nausea and discomfort after eating foods high in sugar or fat, which may signal a hormonal change that also affects the brain’s response.