By Melissa A. Kalarchian, PhD, Marsha D. Marcus, PhD, and Anita P. Courcoulas, MD, MPH
University of Pittsburgh Medical Center, Pittsburgh, PA
Reprinted from Eating Disorders Review
July/August 2008 Volume 19, Number 4
©2008 Gürze Books
Bariatric surgery is recommended for individuals with class III obesity (body mass index, or BMI, > 40 kg/m2) or class II obesity (BMI: 35-40 kg/m2) with obesity-related health problems who have failed previous medically supervised nonsurgical attempts at weight control. Bariatric surgery is associated not only with substantial weight loss, but also with improvement in or resolution of health problems such as hypercholesterolemia, high blood pressure, sleep apnea, and type 2 diabetes. These health benefits are weighed against the immediate and longer-term complications and risks associated with major abdominal surgery, including a small possibility (less than 0.5%) of death.
Candidates for bariatric surgery are evaluated by a multidisciplinary team. The screening process typically includes a comprehensive medical evaluation, as well as a psychological evaluation, nutritional consultation, and education about the surgery and what to expect. Individuals seeking obesity treatment frequently report problems with depression, binge eating or night eating, and candidates for weight loss surgery are no different. Overall, mood and eating are greatly improved soon after surgery, and psychosocial functioning is improved.
The main mechanism by which patients lose weight after bariatric surgery is eating less. Some procedures, such as Laparoscopic Adjustable Gastric Banding (LAP-BAND®), are purely restrictive. Due to their greatly reduced gastric capacity, patients consume less solid food at each meal or snack, and thus lose weight over 2 to 3 years. Other procedures, like Roux-en-Y gastric bypass, combine a small gastric “pouch” with “bypassing” a portion of the upper intestine to create a degree of intestinal malabsorption. Weight loss is more rapid after a procedure combining restriction and malabsorption, and body weight reaches a nadir around 12 to 18 months after gastric bypass.Weight loss following a LAP-BAND procedure is more gradual and, and occurs over a 3-year period.
With any procedure, there is a limited amount of time when patients will lose weight. Afterward, they will transition to a period of long-term adjustment and weight stabilization. A small but significant proportion of patients (approximately 20%) will experience long-term failure, defined as inadequate weight loss or significant weight regain.
Consequences of Malabsorption
Procedures involving malabsorption of food tend to be associated with some additional consequences or complications relative to purely restrictive operations. Malabsorption increases the risk for protein-calorie malnutrition and vitamin or mineral deficiencies, especially deficiencies of vitamin B12, calcium, and iron. Supplementation reduces the risk for protein-calorie malnutrition and vitamin or mineral deficiencies, especially vitamin B12, calcium, and iron. Supplementation reduces the risk of developing nutritional deficiencies but does not eliminate it.
An additional consequence is the “dumping syndrome,” characterized by lightheadedness, sweating, palpitations, cramps, and diarrhea. This usually occurs when a patient consumes too much sugary food, such as ice cream or cake, at one time. Some patients view this complication favorably because it deters them from consuming “junk food,” whereas for others it becomes problematic. Fortunately, the dumping syndrome can be reduced or eliminated with dietary changes.
Eating Problems after Ignoring Dietary Guidelines
Failure to adhere to postoperative dietary guidelines can lead to eating problems. For example, patients may vomit involuntarily after eating too fast, not chewing their food well enough, or overeating. Some will learn to self-induce vomiting to alleviate the discomfort associated with overeating. Much less commonly, self-induced vomiting is used to counteract the effects of eating on body weight and shape. Some patients describe a sensation of “plugging,” or the feeling that food has become stuck in their upper digestive tract or “pouch.” Eating problems like vomiting and plugging tend to improve over time as patients learn to use the results of their surgery as a “tool” to help them eat less. Most patients are eventually able to consume a diet with a range of healthy foods, with the exception of frequent intolerance of red meats and soft white breads.
Certain postoperative eating patterns can lead to inadequate weight loss or even to weight regain. A pattern of frequent snacking or nibbling can interfere with weight loss. Additionally, because surgery does not restrict liquid intake, frequent consumption of high-calorie liquids, like juice or milkshakes, can become problematic. Specifically, these eating patterns make it possible for the surgery patient to consume a large amount of calories despite a reduced gastric capacity. Ultimately, patients who make and sustain healthy changes in their eating patterns, including consuming small portions of mealtime foods and snacks, are most likely to achieve optimal weight control.
Full-onset Eating Disorders
The onset of full-syndrome eating disorders—anorexia nervosa, bulimia nervosa, or binge eating disorder—after surgery is unlikely, but possible. However, it is important to recognize that aberrant eating patterns may develop after the operation that do not meet current diagnostic criteria for eating disorders, but that nonetheless are associated with distress and impaired weight management (see box, left). For example, research studies indicate that the resumption of or onset of loss of control over eating is not uncommon at longer-term follow-up, and may be associated with inadequate weight loss or weight regain.
Segal and colleagues (2004) have observed the co-occurrence of eating disorders and anxiety symptoms in this patient population. As a result, they have proposed a new diagnosis, “postsurgical eating avoidance disorder (PSEAD).” Because patients with a history of eating disorders prior to surgery may be at risk for developing full-syndrome or subthreshold disorders after operation, these individuals may benefit from close follow-up.
Psychiatrists, psychologists, nutritionists, and registered dietitians who treat patients with eating problems after bariatric surgery must work closely with the surgical team to rule out physiological and anatomic-surgical causes. A full diagnostic workup may include laboratory testing, a nutritional evaluation, psychological evaluation, and/or an upper GI series to assess the anatomy and functionality of the altered gastrointestinal tract.
New Assessment Tools for Assessment Are Needed
Currently, standardized assessments for postoperative eating behavior are lacking, and there is a need for new tools to fully characterize the range of eating pathology that can develop after surgery. Having a patient self-monitor his or her dietary intake (including any episodes of vomiting), along with the associated circumstances (including both external factors, such as the type and quantity of food consumed or interpersonal context, and internal factors, such as thoughts and feelings), may serve as the foundation for developing an appropriate individualized cognitive behavioral treatment plan. In extreme cases, a patient may benefit from hospitalization for observation of eating behavior. Interventionists should appreciate that the patients who seek treatment for postoperative eating patterns are not representative of the full spectrum of bariatric surgery patients, most of whom do not experience severe problems.
Summing It All Up
In summary, eating problems after bariatric surgery may include problems associated with malabsorption, including dumping syndrome or nutritional deficiencies; difficulties associated with failure to adhere to the postoperative guidelines for eating, like vomiting or a sensation of plugging; eating patterns associated with poor weight outcome, such as frequent snacking or excess consumption of high-calorie liquids; or eating disorder diagnoses or symptoms, such as loss of control over eating. These problems may be mild for some, but severe for others, causing distress or impairment. Unfortunately, we cannot yet predict who will experience clinically significant eating problems prior to surgery. Multidisciplinary interventions are needed to help patients both prepare for surgery and achieve optimal weight loss and psychosocial adjustment afterward.