The question

People considering gastric bypass surgery often focus on the immediate result: an end to obesity after struggling unsuccessfully to lose weight. Over the long term, though, might the procedure affect their eating and digestion?

This study

The study involved 544 obese adults, most in their mid-40s, including 249 who had laparoscopic gastric bypass surgery. About two years after the start of the study, gastrointestinal complaints — mainly indigestion, abdominal pain and dumping syndrome (rapid emptying of the stomach, resulting in cramps and diarrhea) — were more common among those who had had the surgery than among those who had not.

About 71 percent of the gastric bypass group, compared with 17 percent of the others, could not tolerate certain items, including red meat and foods high in fat or sugar. Water was not tolerated by about 7 percent of those who had had gastric bypass, vs. none of the others. The researchers found no link between the amount of weight people had lost and the digestive problems. In a comment added to the study, the journal’s editor described the number of gastrointestinal complaints as “alarming.”

Who may be affected

People who have gastric bypass surgery to combat obesity. Also known as Roux-en-Y surgery, gastric bypass is the most common type of bariatric, or weight-loss, surgery in the United States. It involves shrinking the stomach to the size of a tiny pouch and reconnecting the small intestine to the pouch, bypassing parts of the original stomach and small intestine that absorb calories from food. After the surgery, less food is required to make a person feel full.

Caveats

Data on gastrointestinal issues came from the participants’ responses on questionnaires. Whether the findings would apply to people who had other types of bariatric surgery was not tested.

Find this study

Online in the British Journal of Surgery (bjs.co.uk; search for “gastrointestinal symptoms”).

Learn more

Information on gastric bypass surgery is available at asmbs.org (click “Patients,” then “Bariatric Surgery Procedures”) and at ­hopkinsmedicine.org.

The research described in Quick Study comes from credible, peer-reviewed journals.