Eating Disorders Before and After Bariatric Surgery

What You Need to Know

Bariatric surgery is often recommended for patients with larger bodies. A large body size, referred to in the medical world as obesity, is not the same as an eating disorder. Yet, there is an intersection. A considerable number of people considering bariatric surgery may have an eating disorder. An existing eating disorder can make the outcome of bariatric surgery worse. Furthermore, the surgery itself may create conditions that cause or mimic eating disorders or disordered eating.

What Is Bariatric Surgery?

Bariatric Surgery, also known as weight loss surgery, refers to a range of procedures that physically alter the structure of the body in order either to restrict the volume of food that can be consumed or to cause nutrient malabsorption in order to produce weight loss.


Restrictive procedures limit food intake by reducing the stomach’s capacity. Such procedures include:

  • Vertical Banded Gastroplasty: using a band and staples to create a small stomach pouch
  • Laparoscopic Adjustable Gastric Banding: placing an adjustable band around the upper part of the stomach to create a small pouch to hold food
  • Sleeve Gastrectomy (Gastric Sleeve): permanently and surgically removing approximately 80 percent of the stomach, leaving a tube-shaped stomach about the size and shape of a banana


There is also a class of procedures referred to as malabsorptive. These shorten the length of the functional small intestine and include procedures such as jejunoileal bypass, which was performed primarily in the 1960s and 1970s. It involved surgically bypassing about 90 percent of the small intestine to short-circuit nutrient absorption; it is no longer performed due to causing severe malnutrition and death.

Another malabsorptive procedure is a biliopancreatic diversion, in which portions of the stomach are surgically removed; the small pouch that remains is connected directly to the final segment of the small intestine, entirely bypassing the upper part of the small intestines. A shared channel remains in which bile and pancreatic digestive juices mix prior to entering the colon. Weight loss occurs because most of the calories and nutrients are routed into the colon and are not absorbed.


Finally, some procedures combine restriction with malabsorption. One such procedure is the Roux-en-Y gastric bypass (RYGB), in which the upper section of the stomach is stapled off, leaving a small gastric pouch which limits oral intake. This pouch is then attached directly to the part of the small intestine called the Roux limb, bypassing the rest of the stomach and the upper part of the small intestine, which further causes mild malabsorption.

Today, the gastric sleeve and the RYGB are the most commonly performed bariatric procedures in the United States.

It is estimated that in 2017, 228,000 total gastric surgeries were performed, 59 percent of which were gastric sleeve and 18 percent RYGB.

Important Considerations

If you have an eating disorder or disordered eating and are considering gastric surgery, it is important to understand that the surgery is not likely to solve the eating disorder or eating issues; it may make it worse. It may not produce permanent weight loss either. What weight loss it does produce will come at a cost.

People undergoing bariatric surgery should carefully consider that bariatric surgery is one of the highest paid surgical specialties, so physicians performing it have a vested interest in encouraging patients to undergo it. They may not adequately prepare patients for some of the risks.

Forced Diet

Critics say that bariatric surgery is merely a forced diet—the various techniques are designed to reduce your stomach’s capacity to hold food or to damage your organs so that they cannot absorb as many nutrients. In short, this is induced malnutrition. Post-surgical nutritional deficiencies are common.


Death is another real possibility. Reported mortality rates for people undergoing bariatric surgery are as high as 5 percent of patients dying within a year—the actual rate may be even higher due to underreporting. One investigative report found that deaths attributable to gastric bypass were not accounted for and recorded as deaths from other causes. Other complications are likely and encompass all bodily systems.

Limited Research

Most of the research on bariatric surgery focuses on outcomes during the first year after surgery—data on long term outcomes is limited. Most studies report outcomes for less than 80 percent of the patients, omitting those who may have dropped out of the study due to poor results and the shame that comes with them. Few studies track results beyond two years post-surgery.

These issues significantly bias the reported results, as noted by one review, “Substantial risks exist for arriving at overly optimistic conclusions regarding the effect of a weight loss intervention when follow-up is incomplete. Because of incomplete follow-up, most bariatric surgery studies may report overly optimistic estimates for these operations’ effects.”

A significant proportion of those undergoing bariatric surgery does not achieve expected weight loss.

Plus, patients who experience less weight loss or patients who regain weight are less likely to show up for follow-up care and more likely to be excluded from the data.

Emerging data suggests the surgery may offer only temporary relief from the medical issues that it is meant to treat and that weight may be gradually regained. Following surgery, patients are generally the same size they were before surgery, and they may not have significantly improved health outcomes.

Some may never be able to eat regularly again or may be limited to eating small amounts and have to permanently avoid certain foods.

Eating Disorders and Bariatric Surgery

Research suggests that eating disorders and problematic eating behaviors are common in those seeking bariatric surgery. Many have engaged in repeated dieting which is a known associate to disordered eating. Existing disorders can significantly impact surgery outcomes. Unfortunately, researchers believe that eating disorder and problematic eating behaviors are likely minimized or underreported by patients electing to have these procedures. These patients may fear that they will not be approved for surgery if they admit to an eating disorder or disordered eating. 

Binge eating disorder (BED), which is characterized by episodes of eating large amounts of food while feeling out of control, is the most common eating disorder reported in patients seeking bariatric surgery. Prevalence rate estimates of BED and bariatric surgery vary greatly due to the use of different criteria and varied assessment methods. However, the range is between 4 percent and 49 percent. However, these may not be accurate figures. It is not known how many patients undergoing bariatric surgery may have other eating disorders including bulimia nervosa and atypical anorexia because these are often overlooked in people in larger bodies.

Impact of Eating Disorders on Bariatric Surgery Outcomes

The impact that eating disorders have on the success of bariatric surgery has proven difficult to study for some of the reasons mentioned above. Some studies suggest that a diagnosis of BED prior to surgery is associated with eating disorder symptoms after surgery and less weight loss or more weight regain.

Unfortunately, patients with eating disorders prior to surgery may be inadequately evaluated and treated.

Individual bariatric surgery programs use their own assessment procedures. There is no universally accepted or recommended practice. Most of the criteria for bariatric surgery focus on a patient having a body over a certain size (measured in body mass index or BMI), having a history of failed weight loss attempts, and lack of psychological contraindications, which are not well-defined. Therefore, eating disorder symptoms may not be adequately assessed.

Eating Disorders After Surgery

Eating disorders after bariatric surgery are difficult to assess and may be under-reported as well. Complications from the surgery can include medical problems and symptoms that can mimic eating disorder behaviors or symptoms, such as vomiting, constipation, and decreased appetite. Other symptoms related to the surgery can lead patients to engage in compensatory behaviors to relieve uncomfortable feelings from having eaten too much or food that is difficult to tolerate.

Bariatric surgery patients experience anatomical and physiological changes that significantly alter their diet and eating behaviors. As a result, eating an objectively large amount of food in one sitting (as required for a diagnosis of BED) may be physically impossible, at least for a period following the surgery.

Thus, existing diagnostic criteria for eating disorders may not adequately reflect the presentation seen in patients after bariatric surgery. Patients may not technically meet criteria for BED even when assessed, even if they have clinically significant eating pathology. Reported prevalence rates of eating disorders in the post-bariatric surgery population may, therefore, be artificially low.

Loss of Control Eating

However, the experience of not being able to control your eating, or "Loss of Control Eating," over smaller amounts of food appears to be commonly reported among patients post-surgery.

Evidence indicates that the experience of loss of control, regardless of the amount of food eaten, may be the most defining feature of binge eating.

Researchers have proposed a diagnosis of “Bariatric Binge-Eating Disorder” to describe those patients who fulfill DSM-5 criteria for binge eating disorder except for the “unusually large” amount of food criterion for binge eating episodes. Preliminary research supports the “presence of an eating disorder very much like binge-eating disorder among a significant subgroup of patients” after bariatric surgery.

Loss of Control Eating is common among bariatric patients. It is found in 13 percent to 61 percent of patients prior to surgery and in 17 percent to 39 percent of patients post-surgically.

Anorexia Nervosa, Bulimia Nervosa, and OSFED

While little is known about rates of bulimia nervosa before or after surgery, case reports of bulimia nervosa after bariatric surgery have been reported. Similarly, rates of anorexia nervosa prior to surgery are not reported (and not often diagnosed in patients in larger bodies), but among patients who have had bariatric surgery, several case reports describe patients with atypical anorexia.

This refers to people who meet all the criteria for anorexia nervosa except for the objectively low weight. This points further to evidence that bodies are naturally diverse and that extreme weight loss can be detrimental.

Night eating syndrome, currently classified as a type of Other Specified Feeding or Eating Disorder in the DSM-5, is characterized by episodes of awake nighttime overeating and a disrupted circadian rhythm. It has also been documented in patients after bariatric surgery with prevalence rates ranging from 2 percent to 18 percent.

Additional Eating Behaviors Post-Surgery

Bariatric surgery patients are instructed to change their eating behaviors after surgery. They are instructed to limit meal size and to chew food extensively. They are asked to follow strict schedules, weigh and measure their food, and avoid specific foods. In the general population, these exact behaviors are often diagnosed as symptoms of eating disorders.

In fact, the preoccupation with maintaining weight loss and avoiding weight regain prescribed for bariatric surgery patients is very similar to what is observed in an eating disorder.

This may lead one to wonder if bariatric surgery is just teaching people how to have a more restrictive eating disorder.


Episodic vomiting appears to be relatively common after bariatric surgery. Individuals may vomit deliberately or spontaneously after eating certain intolerable foods or after eating too quickly or chewing inadequately. Some doctors may even encourage periodic vomiting to relieve uncomfortable physical symptoms.

Even when it occurs initially spontaneously, patients may learn to do it deliberately, believing it will help control their weight. Frequent vomiting, however, can cause electrolyte imbalances, which can lead to cardiac arrhythmia—in some cases, this can cause sudden death.

What Is Dumping?

Dumping (the failure of food to digest, bringing increased fluid into the small intestine and causing extreme diarrhea) occurs post-surgery for many patients after consuming sweets or large quantities of food. Patients will often complain about lightheadedness and sweating after eating a high-glucose meal or consuming a large meal. This is extremely uncomfortable and accompanied by intense fatigue.

Dumping is another post-surgery behavior that is sometimes used deliberately for weight loss or to try to compensate for food eaten.


Grazing (the repetitive eating of small amounts of food in an unplanned manner and/or not in response to hunger) is a newly recognized behavior. To be repetitive, it must occur twice in the same period during the day (i.e., in the morning). It is suggested that there are two types: compulsive with a loss of control, and non-compulsive, which is distracted and mindless but without loss of control.

Grazing is distinguished on the one hand from binge eating episodes by the amount of food eaten, and on the other hand from Loss of Control Eating by its lack of a circumscribed period of time. Grazing may be a natural response to the shrunken capacity of the stomach as an individual may not be able to take in the amount of food one requires at a single meal.

Grazing is estimated to occur in up to 47 percent of patients after surgery. Picking or nibbling—patterns of repetitive and unplanned eating—are similar to grazing. Some patients may also engage in chewing and spitting.

Loose Skin

Loose skin, which is common after surgery, can increase body dissatisfaction. A cruel irony is that the dissatisfaction with one's body size that existed before the surgery may not be alleviated but instead replaced by concern over the loose skin.

In Conclusion

Post-operative Loss of Control Eating and binge eating are both associated with less weight loss and more psychosocial problems. Unfortunately, post-surgical psychological support is not uniformly provided.

There are no established treatments specifically for patients with eating disorders or problematic eating post-bariatric surgery. Cognitive-behavioral therapy (CBT) is the psychological treatment with the most support for adults with eating disorders including BED and bulimia nervosa and thus might be helpful for patients with post-bariatric eating disorders and disordered eating.

People with larger bodies may feel desperate to have surgeries that they believe will improve health and solve their lifelong struggles with their weight. Indeed, weight stigma and judgment against fat people is commonplace. Doctors will often encourage surgery. However, people undergoing bariatric procedures are facing serious medical complications and often exchanging one problem—dissatisfaction with their body size—for others, such as permanent health problems and a potential eating disorder. Patients should be better informed about the potential risks.

A Word From Verywell

If you have an eating disorder and are contemplating gastric surgery, it may be more advisable to first receive eating disorder treatment, ideally from a therapist who practices a Health at Every Size® approach and does not have a vested interest in your surgery decision. You may find that there are other ways to improve your health without surgery. If you’ve had bariatric surgery and are experiencing any of the above symptoms, you are strongly encouraged to seek help from an eating disorder specialist. 

Don't underestimate the power of speaking to a mental health professional to encourage your best eating habits and healthiest body, both mentally and physically.

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Article Sources

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