The study followed 60 severely obese patients who were randomly assigned either gastric bypass surgery or a rarer, more extensive procedure known as duodenal switch.
A duodenal switch involves removing part of the stomach, and the remaining part of the stomach is attached to the final section of the small intestine, placing even greater limits on the body's absorption of calories and nutrients.
At the two-year follow up, duodenal switch patients had lost more weight: about 50 pounds more on average.
Weight loss was profound with both kinds of surgery: gastric bypass patients lost an average of 111 pounds, while duodenal switch patients lost about 162.
However, those extra pounds came at the added risk nearly double the complication rate.
Of the 29 patients that underwent a duodenal switch, 62 percent had problems like abdominal pain, vomiting, diarrhea and intestinal obstruction. Several suffered long-term malnutrition, a side effect not seen in the gastric bypass group.
Duodenal switch is a relatively rare procedure -- it accounted for just one percent of weight-loss surgeries done in the U.S. in 2008 and five percent in Europe.
"This is an operation that should probably go away," said Dr. Edward H. Livingston, a professor and surgeon at the University of Texas Southwestern Medical Center in Dallas, according to Reuters.
The risks of nutrient deficiency are far greater in a duodenal switch, he continued, advising patients contemplating weight loss surgery to avoid it entirely.
"It's just not a good operation," he asserted.
