The Effect of Gastric Bypass on Glucose Levels

While gastric bypass surgery is effective not only in weight loss, but improving a number of health conditions, it seems to have one disadvantage: raising glucose levels. In a recent study conducted by Mitchell S. Roslin, MD and researchers at Lenox Hill Hospital in New York City, found a considerable spike in glucose (blood sugar) levels after eating a meal. The study looked at various types of bariatric weight loss surgeries, including gastric bypass. The results of this study appeared at the Society of American Gastrointestinal and Endoscopic Surgeons meeting in 2013, and were sponsored by Covidien.

The Study on Glucose Levels

The study included a total of 38 patients, 13 of whom had gastric bypass, 12 had a sleeve gastrectomy and 13 had the duodenal switch procedure. This allowed researchers to look at the glucose metabolism of each patient according to the type of weight loss procedure performed. Each of them had an oral glucose tolerance test (GTT) at the start of the study, as well as at 6, 9 and 12 month increments. For the GTT, the patients were advised to eat a mixed-meal muffin. The only real difference in patients for this study was that patients who had the duodenal switch procedure had a higher body mass index (BMI) than the other two groups.

The Results

The final results showed a significant decrease in weight and BMI for the duodenal switch patients. Each of the three groups of patients also showed a reduction if fasting blood glucose levels. However for the GTT following the muffin, the group of gastric bypass patients had a spike of their blood glucose levels, which was higher than the other two groups. After gastric bypass, these patients also showed higher one-hour insulin levels. This may signal as to why gastric bypass patients tend to have more hunger in between meals, as opposed to getting the duodenal switch or sleeve gastrectomy procedures.

Moving Forward

Researchers make it a point to mention that while this doesn’t say what the potential long-term effects could be, it may give some patients more information moving forward with their procedure. They might have a slightly higher risk of increased hunger between meals with gastric bypass, though the weight loss is just as significant as other weight loss procedures.

Not only does this and similar studies show the difference in weight and glucose levels, but also in the difference in the patient’s metabolism.