Weight-Loss Winner: Gastric Bypass Works Better for Obese Patients

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In head-to-head comparisons of the most commonly used weight-loss surgeries in the U.S., researchers found that gastric bypass worked best for weight loss, reduction of diabetes symptoms and quality of life.

The two new studies published in the Archives of Surgery compared gastric bypass to two other surgical procedures: Lap-Band surgery, which the Food and Drug Administration (FDA) approved for an additional 11 million Americans last week, and sleeve gastrectomy.

All three surgeries involve reducing stomach size, but in different ways. In gastric bypass, a section of the stomach is stapled off, and food is rerouted to bypass the small intestine. In gastric banding, surgeons place an inflatable band around the upper stomach, which limits the amount the stomach can hold. Finally, in sleeve gastrectomy, the least popular of the three procedures, the stomach is surgically narrowed to reduce capacity. (More on TIME.com: Weight-Loss Surgery May Change the Shape of the Heart)

In the first study, researchers from University of California, San Francisco, compared outcomes in 100 patients who had received gastric bypass and 100 others who received Lap-Band. All patients qualified as morbidly obese before surgery, with a body mass index over 40. In each group, 34 patients had been diagnosed with Type 2 diabetes.

One year after surgery, gastric-bypass patients had lost an average of 64% of their excess weight, while the gastric-banding group had lost 34%. What’s more, about 25 of the 34 gastric-bypass patients with diabetes saw their symptoms improve or even disappear; six of the eight patients who had needed insulin were able to stop using it. In the Lap-Band group, 17 of 34 diabetes patients had symptom improvement or resolution.

As for complications, there was little difference between the groups: 12% of gastric-bypass patients reported complications from surgery, including infections, internal bleeding and blood clots, while 15% of Lap-Band patients reported the same. However, gastric-bypass patients reported more complications immediately after surgery. In the year following the initial procedure, 13% of Lap-Band patients needed further surgery, compared with 2% of gastric bypass patients. (More on TIME.com: Why White Girls Are Getting More Weight-Loss Surgery)

In the second Archives paper, a double-blind randomized controlled trial, Taiwanese doctors assigned 30 patients to gastric bypass and another 30 to sleeve gastrectomy. All were moderately obese with Type 2 diabetes. A year after surgery, 93% of gastric-bypass patients no longer had diabetes symptoms, compared with 47% of sleeve-gastrectomy patients. Both groups had significant weight loss at the one- and three-month follow-ups, but by a year after surgery, the gastric-bypass patients had lost more.

The L.A. Times‘s Booster Shots blog reports:

The finding — that diabetes improved with gastric bypass but not with gastric sleeving — offered an important clue to why gastric bypasses seem to improve the metabolic function of diabetics virtually overnight. Neither sleeve gastrectomy nor the Lap-Band causes food to bypass any part of the intestine, suggesting that hormones in that part of the gut may play a key role in the changes that lead to diabetes.

“We need to just register that gastric bypass is the gold standard for diabetic control in overweight patients,” said Beverly Hills-based weight-loss surgeon Ted Khalili, director of the Khalili Center for Bariatric Care, who was not involved in the study.

But Khalili, whose practice is roughly split between Lap-Band and gastric-bypass surgery, added that the U.C. San Francisco findings are far less clear for patients whose primary objective is to lose weight. Although more weight loss was seen for the gastric bypass group in the one-year study, patients getting the Lap-Band continue to lose weight for two to three years after the procedure, Khalili said. Comparing the two patient populations three years after surgery would probably have narrowed the weight-loss gap considerably, Khalili said.

The U.C. San Francisco authors also note that their findings apply only to gastric-bypass procedures done at high-volume centers by experienced surgeons. Gastric bypass is considered riskier and more technically demanding of the surgeon, compared with the other weight-loss surgeries.

More on TIME.com:

Is School Lunch Making Your Kids Fat?

Babies Who Start Solids Too Early More Likely to Be Obese

Are Working Moms to Blame For Childhood Obesity?

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