Eating Disorders Before and After Bariatric Surgery–What You Need to Know

Health professionals often recommend bariatric surgery for patients with larger bodies. A large body size, referred to in the medical world as “obesity,”—a term we will not use unless citing medical data— 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. Most will have dieted numerous times and will have at least disordered eating. 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.

Most of the writing about bariatric surgery is highly fatphobic and written by people and organizations who profit from performing the surgery. We will be discussing it more critically from a weight-inclusive, anti-diet approach.

What is Bariatric Surgery?Eating Disorders and Bariatric Surgery [Image description: purple scrabble tiles spelling "Eating Disorders and Bariatric Surgery"]

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

Restrictive Procedures

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, or 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

Malabsorptive Procedures

Malabsorptive procedures shorten the length of the functional small intestine and include procedures such as:

  • Jejunoileal Bypass—a procedure performed primarily in the 1960s and 1970s that 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
  • 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 that 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 US. It is estimated that in 2017, 228,000 total gastric surgeries were performed, 59% of which were gastric sleeve and 18% RGBY.

What to Consider Before Undergoing Bariatric Surgery

Potential Bariatric Surgery Client in Californai [Image description: a black woman in a larger body smiling and sitting in a waiting room]
Photo by AllGo – Unsplash
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. And, it may not solve your weight issues either.

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

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: induced malnutrition. Post-surgical nutritional deficiencies are common. The caloric levels recommended for people who have undergone the procedure are simply too low.

Substantial Risks

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.

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% 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 2 years post-surgery. These issues significantly bias the reported results, as noted by Puzziferri, et al.: “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.” (2014, p. 940).

Limited Weight Loss and Regain

Furthermore, a significant proportion of those undergoing bariatric surgery do not achieve expected weight loss or regain a significant portion of the lost weight over time. Those patients with less weight loss or more weight regain are less likely to show up for follow-up care due to shame and not be included in 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 still large, though less so, and 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 avoiding certain foods.

Prevalence of Eating Disorders in People Seeking Bariatric Surgery

Research suggests that eating disorders and problematic eating behaviors are common in those seeking bariatric surgery, possibly because they may have engaged in repeated dieting which is a precursor to disordered eating.  Existing disorders can significantly impact surgery outcomes. Unfortunately, researchers believe that eating disorders and problematic eating behaviors are likely minimized or underreported by patients electing to have these procedures. They 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 vary greatly due to the use of different criteria and varied assessment methods and range from 4% to 49%. But these may not be accurate as explained above.

Impact of Eating Disorders on Bariatric Surgery Outcomes

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

Unfortunately, patients with eating disorders before 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 BMI), having a history of failed weight loss attempts, and lack of psychological contraindications, which are not well-defined. Consequently, eating disorder symptoms may not be adequately assessed.Binge Eating Disorder Therapy In Los Angeles, California [Image description: drawing of two adults in therapy chairs representing a potential adult seeking therapy for bulimia nervosa in Los Angeles, CA]

Eating Disorders After Surgery

Eating disorders after bariatric surgery are difficult to assess and may be underreported. We see them in this office. 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 the criteria for BED even when assessed although 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 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, maybe 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” 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 (Ivezaj et al.2018, p. 28).

Loss of Control Eating is common among bariatric patients. It is found in 13% to 61% of patients before surgery and in 17% to 39% of patients post-surgically (Ivezaj et al, 2021). This makes sense when your stomach capacity is physically restricted because restriction is a significant driver of rebound eating.

Exercise in Eating Disorders [Image description: photo of a mid-size woman with pink hair lifting heavy weights in a gym]
Image by Body Liberation Photography

Bulimia and Anorexia

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 before 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, meaning people 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

Night eating syndrome (NES), a proposed diagnosis, is currently classified as a type of Other Specified Feeding or Eating Disorder.  NES 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% to 18%.

Additional Problematic Eating Behaviors After 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 must 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. The preoccupation with maintaining the weight loss and avoiding weight regain prescribed for bariatric surgery patients is so like what is observed in an eating disorder, that one may wonder, “Are we 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 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 a cardiac arrhythmia that can cause sudden death. It can also damage the esophagus.


Dumping is the failure of food to digest. It brings increased fluid into the small intestine and causes extreme diarrhea. Dumping occurs post-surgery for many 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. Some individuals use dumping 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. morning). It is suggested that there are two types: compulsive with a loss of control, and non-compulsive—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 circumscribed period.

When the capacity of the stomach is shrunken and an individual cannot take in the amount of food one requires at a single meal, grazing may be a natural response. Grazing is estimated to occur in up to 47% 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.

Excessive Restriction

Excessive dietary restriction. An unknown percentage of individuals who have had bariatric surgery appear to develop restrictive eating disorders that look like anorexia nervosa. Of course, this is what the surgery and recommended dietary guidance reinforce so is unlikely to be identified. We know individuals at higher weights can meet the criteria for atypical anorexia. These individuals experience all of the same risky effects of restriction as people with low-weight anorexia.

Loose Skin

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

Help for People with Eating Disorders Before and After Bariatric Surgery

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 recommended psychological treatment for adults with eating disorders. CBT addresses BED and bulimia nervosa. It can also be helpful for patients with post-bariatric eating disorders and disordered eating.HAES-aligned recovery and standing up to diet culture in Los Angeles, California [Image description: 2 females eating ice cream cones joyously] Represents potential people with eating disorders in recovery in Los Angeles, California

People with larger bodies may feel desperate to have these surgeries, They are told they will improve health and solve their lifelong struggles with their weight. Indeed, weight stigma and dislike of fat people are commonplace. Doctors will often encourage the surgery. However, people undergoing bariatric procedures are facing serious medical complications. As well, they may be exchanging one problem—large body size—for others—permanent health problems and a potential eating disorder. Patients should be better informed about the potential risks.

Get Help for an Eating Disorder Before or After Bariatric Surgery in California

If you have an eating disorder and are contemplating gastric surgery, please reach out for help. You deserve eating disorder treatment, ideally from a therapist who practices a Health at Every Size® approach. Please see a therapist who does not have a vested interest in your surgery decision. If you’ve had bariatric surgery and are experiencing any of the above symptoms, we encourage you to seek help from an eating disorder specialist.

Our caring eating disorder specialist therapists can help! Simply complete the contact form on our website or give us a call. Please note that we do not perform bariatric surgery assessments.


American Society for Metabolic and Bariatric Surgery (2018). Estimate of Bariatric Surgery Numbers, 2011-2017.

Conceição, Eva M., Linsey M. Utzinger, and Emily M. Pisetsky. 2015. “Eating Disorders and Problematic Eating Behaviours Before and After Bariatric Surgery: Characterization, Assessment and Association with Treatment Outcomes.” European Eating Disorders Review 23 (6): 417–25.

Ivezaj, Valentina, Erin E. Kessler, Janet A. Lydecker, Rachel D. Barnes, Marney A. White, and Carlos M. Grilo. 2017. “Loss-of-Control Eating Following Sleeve Gastrectomy Surgery.” Surgery for Obesity and Related Diseases: Official Journal of the American Society for Bariatric Surgery 13 (3): 392–98.

Ivezaj V, Carr MM, Brode C, Devlin M, Heinberg LJ, Kalarchian MA, Sysko R, Williams-Kerver G, Mitchell JE. Disordered eating following bariatric surgery: a review of measurement and conceptual considerations. Surg Obes Relat Dis. 2021 Aug;17(8):1510-1520. doi: 10.1016/j.soard.2021.03.008.

Lim, Robert B. 2017. UpToDate: Bariatric procedures for the management of severe obesity: Descriptions. Wolters Klewer.

Marino, Joanna M., Troy W. Ertelt, Kathy Lancaster, Kristine Steffen, Lisa Peterson, Martina de Zwaan, and James E. Mitchell. 2012. “The Emergence of Eating Pathology after Bariatric Surgery: A Rare Outcome with Important Clinical Implications.” The International Journal of Eating Disorders 45 (2): 179–84.

Meany, Gavin, Eva Conceição, and James E. Mitchell. 2014. “Binge Eating, Binge Eating Disorder and Loss of Control Eating: Effects on Weight Outcomes after Bariatric Surgery.” European Eating Disorders Review : The Journal of the Eating Disorders Association 22 (2): 87–91.

Puzziferri, Nancy, Thomas B. Roshek, Helen G. Mayo, Ryan Gallagher, Steven H. Belle, and Edward H. Livingston. 2014. “Long-Term Follow-up after Bariatric Surgery: A Systematic Review.” JAMA 312 (9): 934–42.

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