Is gastric bypass more beneficial for diabetes patients than traditional weight loss?

In recent years, some researchers have suggested that gastric bypass surgery can provide patients with additional benefits outside weight loss. Is this really the case? A group of researchers has explored this very subject, sharing its findings in the New England Journal of Medicine.

The study’s authors explored data from 22 obese patients with type 2 diabetes. While eleven of those patients underwent Roux-en-Y gastric bypass surgery, the other eleven worked to lose weight through an improved diet. The diet group was provided with prepacked food and “weekly education sessions on dietary practices” to assist with their progress.

The study lasted nearly four years, from November 2014 to October 2018.

So how did the two groups compare to one another? Overall, there were no significant differences when it came to the benefits related to multiorgan insulin sensitivity, beta-cell function and 24-hour plasma glucose and insulin profiles.

The patients’ weight loss did affect these areas, of course, but the benefits were “nearly identical” whether the patient lost weight due to gastric bypass surgery or improving their diet.

The research team did observe certain differences in the two groups, detailing them in its analysis—but the changes did not lead to differences in metabolic function.

“We found that patients in the surgery group had a greater decline in plasma concentrations of branched-chain amino acids and C3 and C5 acylcarnitines and a greater increase in plasma bile acids than patients in the diet group—a finding consistent with results from previous studies,” wrote lead author Mihoko Yoshino, MD, PhD, Washington University School of Medicine in St. Louis, and colleagues. “The changes observed in the gut microbiome of persons in the surgery group are also consistent with the results from most studies and were much greater than the changes observed in the diet group.”

At the end of the day, Yoshino et al. noted that their study’s findings “underscore the profound effect that  marked weight loss can have on metabolic function in people with diabetes.”

“The similar findings in participants in the two groups challenge the current belief that upper gastrointestinal bypass has clinically meaningful effects on key metabolic factors involved in glucose homeostasis and the pathogenesis of diabetes that are independent of weight loss,” the authors concluded. “However, the difficulty in achieving successful long-term weight loss with lifestyle therapy often renders gastric bypass surgery far more effective than diet therapy for most patients with obesity and type 2 diabetes.”