(NEW YORK) -- When multiple traditional diet methods fail, weight-loss procedures such as lap band surgery are seen as a last hope for getting obese patients to eat more healthfully and lose weight.
But for an under-recognized minority of patients, the surgery only triggers a different kind of disordered eating. For some, it's bulimia, while for others, it's anorexia.
Sixty percent of individuals seeking treatment for obesity have some kind of eating disorder, usually binge eating, according to a 2007 Harvard study. It is these individuals, who already have an unhealthy relationship with food and their bodies, who are at most risk of developing further eating disorders post-surgery, says Lisa Lilenfeld, a psychologist and president of the Eating Disorders Coalition at Argosy University in Washington, D.C.
Lap band or gastric bypass surgery is not likely to create an eating disorder where there wasn't one, she explains, but "the most likely thing is that people had untreated or unsuccessfully treated binge eating disorders before surgery will continue to have problems after surgery. The problem is, it becomes physically challenging and potentially dangerous to binge like this because of the structural changes in the stomach," she says.
On the other end of the spectrum, patients who used to overeat now overshoot with their weight loss, severely limiting their caloric intake to the point of malnutrition and anorexia.
"I've had a number of patients go from very obese to very underweight, so much so that they need to be rehabilitated with intravenous nutrition," says Dr. Donald Kirby, a gastroenterologist at the Cleveland Clinic who treats patients undergoing bariatric weight-loss surgery.
Because there are still no statistics on how many of these patients experience eating disorders post-op, it's difficult to gauge the scope of this issue and there is much debate over its prevalence between the surgeons who perform the procedures and the therapists who treat eating disorders down the line.
Dr. Mitch Roslin, a bariatric surgeon at Lenox Hill Hospital in New York, has performed thousands of bariatric surgeries and he says he only sees one or two cases a year of eating disorders, but psychologist Lilenfeld believes it's much more common than that.
Copyright 2011 ABC News Radio