Medical Management of Severe Eating Disorders

By Philip Mehler, MD, FACP, FAED, CEDS | Published 12/1/2020 1

young woman anorexia eating disorders

Anorexia nervosa is considered the deadliest of all mental illnesses. (Photo source: iStock)

Severe eating disorders are the only mental illnesses regularly accompanied by dangerous, life-threatening medical complications. Significant medical instability results from a number of abnormalities, such as progressive malnutrition, purging behaviors, and blood chemistry abnormalities.

In fact, the disorder can compromise virtually all of the body’s vital organs and systems.

There are a number of different eating disorders that lead to excessive weight loss and associated medical complications. The most common include:

In this article, I will focus on the medical complications of these disorders. I will also discuss how to manage because it is crucial to saving the lives of individuals suffering with a severe eating disorder. Further, it is key to helping patients achieve the medical stability and cognitive function necessary to engage fully in the recovery process.

Related content:
What You Need to Know About Eating Disorders
Eating Disorders: Risk Factors, Diagnosis, Treatment, and Outcomes

Medical complications of severe eating disorders

Common medical complications associated with severe eating disorders include the following [1,2]:

      • Gastrointestinal complications, including diarrhea, delayed gastric emptying (gastroparesis), constipation, abdominal pain, and swallowing difficulties) 
      • Liver function test abnormalities
      • Electrolyte abnormalities
      • Pseudo-Bartter’s syndrome (a complex of metabolic abnormalities related to purging)
      • Eye pain
      • Edema
      • Osteoporosis and osteopenia,
      • Superior mesenteric artery (SMA) syndrome
      • Cardiac dysfunction & arrhythmias
      • Muscle weakness
      • Traumatic falls

Medical complications of eating disorders can be treated effectively

The good news is that nearly all medical complications of eating disorders can completely resolve with safe nutritional rehabilitation and weight restoration. This is true regardless of how extensive they are.

Patients are resilient if they get the correct (and timely) treatment with a balance of informed medical and psychiatric care. This is especially critical for more chronic patients and patients of advanced age.

The bad news, however, is that eating disorders themselves are commonly undertreated. This means that a large number of patients receive only partial treatment for the complex medical and psychiatric concerns associated with these illnesses.

It is important to understand that severe eating disorders can be deadly. Anorexia nervosa, for example, is considered the deadliest of all mental illnesses with a mortality rate estimated to be ~10%. [3]  Further, AN patients carry an increased risk for suicide.

Many patients with severe eating disorders will require a high level of care

More than one-third of individuals suffering from eating disorders will require treatment at a higher level of care. This can range from 24-hour inpatient psychiatric care to comprehensive daytime behavioral programming. 

Most treatment programs offer some degree of minimum internal medicine and/or nursing support to manage medical issues of eating disorders. However, some patients may be so medically compromised by their illness that they require specialized medical, hospital-based stabilization prior to entering a residential eating disorder treatment program.

Determining what level of care a patient with an eating disorder needs can be challenging for reasons that include:

      • patient resistance,
      • secrecy shrouding eating disorder behaviors and symptoms,
      • the body’s ability to feign stability.

Determining the appropriate level of care needed

It is not uncommon for patients, families, and providers to begin with the least intensive intervention. However, starting a treatment plan with the appropriate level of care can have a significant impact on the patient’s health. It is also a factor that influences success in recovery and satisfaction with treatment.[4]

The American Psychiatric Association (APA) has outlined five levels of psychiatric care. They are divided between outpatient and inpatient treatments.

It is important to note, however, that this guidance fails to completely outline a crucial sixth level of care. This is the one that involves specialized medical treatment for individuals experiencing extreme medical instability that results from physical complications of malnutrition and purging. 

For this severe subset of patients, intervention should include medical stabilization in a specialized, hospital-based medical unit prior to beginning traditional behavioral eating disorder treatment.

Expert consensus suggests inpatient stabilization should occur when a BMI is <14 or when that patient’s weight is <70% of ideal body weight (IBW).

  • Weight specific recommendations to levels of care

In general, patients with AN or Avoidant/Restrictive Food Intake Disorder (ARFID) whose weight is:

      • below 70% IBW should first be treated in a specialized medical unit for the medical stabilization of those patients,
      • between 70 to 84% of IBW, are best served in an inpatient or residential treatment center,
      • between 85% to 95% of IBW, a partial hospitalization program (PHP) is generally appropriate.[5]

It is important to remember that no guideline is absolute when it comes to these complex illnesses. The frequency of purging behaviors and other physical or psychiatric symptoms must be considered alongside patient weight to ascertain the appropriate level of care that may be needed.

What is inpatient medical stabilization for eating disorders?

In general, initial medical stabilization in a hospital-based unit is recommended for eating disorder patients who are severely low weight, seriously medically compromised, or at risk for major complications from refeeding syndrome. The latter is a dangerous metabolic disturbance that can occur when nutritional rehabilitation is first initiated.

Patients with any/all of the following criteria may require medical treatment from experienced providers in a specialized medical hospital unit before entering a behavioral treatment program in a traditional eating disorder unit:

      • weight <70 percent of ideal body weight or BMI <14
      • unstable vital signs such as low or irregular heart rates or low blood pressure
      • cardiac disturbances such as abnormal heart rhythms or heart failure
      • loss of consciousness due to low blood pressure
      • acute kidney or liver failure and/or
      • critical electrolyte abnormalities such as low potassium or low phosphorous of extreme degrees.

What is the goal of medical stabilization of patients with severe eating disorders?

The goals of medical stabilization are to improve and normalize the patient’s vital signs, cardiovascular system, and bowel function as well as restore levels of key electrolytes including phosphorus, potassium, magnesium, and calcium in a timely manner. Medical stabilization also involves nutritional rehabilitation to support weight restoration.

Most experts agree that careful caloric initiation is vital to medical stability and improved cognitive function. It is hallmarked by the ability to tolerate and complete the most basic activities of daily living. Inpatient medical units have the expertise and resources to deliver any form of nutrition required, including oral, enteral, or intravenous calories.

It is important that each of these goals is met in order for a patient with an eating disorder to be considered medically stable. Once the patient has achieved medical stability, he or she can continue in recovery by transitioning to a 24-hour psychiatric facility. It is important that the psychiatric facility has the ability to sustain medical progress while incorporating the following interventions:

      • intensive psychotherapy,
      • ongoing weight restoration,
      • other evidence-based recovery interventions.

Understanding the difference between medical and psychiatric treatment 

It is also important that providers, patients, and families understand the difference between inpatient psychiatric treatment and inpatient medical stabilization for the most severe eating disorders.

While an inpatient psychiatric facility offers round-the-clock behavioral treatment and likely some degree of medical support, an inpatient medical stabilization program requires a hospital-based telemetry unit.

Its full-time internal medicine physicians, nurses, dietitians, and skilled rehabilitation providers expertly treat any life-threatening medical complication of severe eating disorders. These medical teams collaborate with psychiatrists, psychologists, and behavioral health technicians to support behavioral recovery.

It is important for patients and families to understand that patients with serious complications due to eating disorders will be too weak, medically unstable, or cognitively impaired to engage in meaningful therapy during medical hospitalization.

Inpatient medical and inpatient psychiatric programs must work together to support survival and recovery in medically complex patients. Initially, however, there is no substitute for 24/7-available medical, dietary, and nursing expertise on a dedicated medical stabilization unit.

Avoiding refeeding syndrome

Increasing caloric intake quickly in individuals with severe anorexia nervosa or ARFID, without frequent monitoring of blood tests and electrolyte replenishment, can lead to refeeding syndrome. A dangerous shift in fluids and electrolytes within the body are characteristic of the disorder.

It occurs in a small subset of patients when calories are introduced quickly, lab tests are not checked frequently, and resultant abnormalities are not treated in a timely fashion. The lower the patient’s BMI, the greater the risk of refeeding complications.[6]  

  • Cardiac complications of refeeding

When the body is starved or severely malnourished, the heart muscle may atrophy. This causes diminished cardiac output. Further, the body begins to break down its own tissues—including fats and muscle—in an attempt to create the energy needed to maintain basic bodily functions. These changes can affect the body’s major electrolytes, including phosphorus, potassium, and magnesium.

  • A shift to carbohydrate metabolism

When food is reintroduced during the refeeding process, there is an abrupt shift from fat and muscle metabolism back to carbohydrate metabolism.  This increases the body’s uptake of phosphorus and other key electrolytes into newly developed cells. This leads to dangerously decreased levels of these electrolytes in the blood.

This sudden change in the balance of electrolytes causes the atrophied heart to work harder, which can cause irregular heartbeat, muscle damage, weakness, seizures, and even death. When the resultant blood chemistry abnormalities are not detected or are not addressed in less than a few hours, patients may be at risk for the refeeding syndrome characterized by the following:

        • cardiac failure, 
        • respiratory failure,
        • rhabdomyolysis (muscle death),
        • hemolysis (red blood cell rupture) and/or
        • seizures.

These life-threatening complications are preventable when refeeding is administered by eating disorder experts. However, many medical providers are not trained to identify or address refeeding syndrome in patients with extreme anorexia and ARFID. This unfortunate reality underscores the need for severely underweight patients to begin the refeeding process in a specialized inpatient medical setting capable of treating the most serious eating disorders.

Eating disorder patients with normal or high BMI

Assuming that patients with a “normal” or “higher” BMI are always stable enough to access lower levels of care may inadvertently cause harm. Some of these patients may present with a falsely elevated weight.

They can also be at risk for dangerous complications due to excessive purging behaviors followed by abrupt cessation or significant and rapid “weight disruption” that is marked weight loss over a short period of time.[6]

Thus, regardless of current weight, it is essential to consider the severity of purging behaviors and absolute weight loss when choosing an appropriate level of care.

Again, consider medical stabilization first for those showing severe weight disruption (more than 25% body weight loss in a short time period). Include as well those needing to safely “detox” from severe self-induced vomiting and laxative or diuretic abuse.

The bottom line on the management of severe eating disorders

Eating disorders at any stage are complex and can be life-threatening. Seeking treatment for a severe eating disorder can be overwhelming. This is especially true when life-threatening medical complications are present. However, helping providers, patients, and families understand which level of care provides adequate medical support to address these complications and restore medical stability is an important first step in the recovery journey.


1. Cost J, Krantz M, Mehler P. Cleveland Clinic Journal of Medicine, Medical complications of anorexia nervosa. (2020) 87 (6) 361-366; DOI:

2. Mehler, P. International Journal of Eating Disorders, Medical complications of bulimia nervosa, and their treatments. (2011) 44(2):95-104. DOI: 

3. Berends, T, Boonstra N, van Velburg A. Current Opinions in Psychiatry, Relapse in anorexia nervosa: a systematic review and meta-analysis. (2018) 31(6): 445-455. Doi: 10.1097/YCO.

4. Cost J, Mehler P. Eating Disorders Review, Level of Care Considerations for Severe and Extreme Eating Disorders. (2019), Vol 30. 

5. Mehler P, Crews C. Eating Disorders-The Journal of Treatment and Prevention, Refeeding the Patient With Anorexia Nervosa. (published online 2010)

6 Garber, A. K.. Journal of Adolescent Health. Moving beyond “skinniness”: presentation weight is not sufficient to assess malnutrition in patients with restrictive eating disorders across a range of body weights. (2018), 63(6), 669-670.

Philip Mehler, MD, FACP, FAED, CEDS


Dr. Mehler, MD, FACP, FAED, CEDS attended the University of Colorado School of Medicine and graduated with honors and Alpha Omega Alpha (AOA) and completed his internship and residency in Internal Medicine at from the University of Colorado where he served as Chief Medical Resident. He is a Fellow of the American College of Physicians (FACP), a Fellow of the Academy for Eating Disorders (FAED), and a Certified Eating Disorder Specialist (CEDS), a prestigious clinical credential issued by the International Association of Eating Disorders Professionals (IAEDP). He is also certified by both the American Board of Internal Medicine (ABIM) and the American Board of Addiction Medicine (ASAM).

He is an active member in many professional societies, including Phi Beta Kappa, Alpha Omega Alpha Honor Medical Society, the American College of Physicians, the American Society of Addiction Medicine, the Society of General Internal Medicine, the Academy for Eating Disorders, the American College of Medical Quality, the Eating Disorders Research Society and the International Association of Eating Disorders Professionals.

Dr. Mehler is the founder and Chief Executive Officer of the ACUTE Center for Eating Disorders at Denver Health, the only designated Center of Excellence treating the most extreme forms of eating disorders and malnutrition

In addition to his work with ACUTE, Dr. Mehler has held various leadership roles with Denver Health since beginning his career there more than 35 years ago. He was formerly its Chief of Internal Medicine; he was Chief Medical Officer (CMO) for 10 years until he was promoted to Denver Health’s Medical Director, a position he held until his retirement from administration in 2014. He is also the Glassman Professor of Medicine at the University of Colorado School of Medicine, where he trains the next generation of physicians to identify and address the deadly complications of eating disorders and severe malnutrition, and has taught medical students and residents since 1986.

Following more than 30 years in the field of eating disorders, during which time he has successfully treated thousands of patients and families and published hundreds of articles on effective medical treatment of eating disorders, Dr. Mehler is widely considered the international authority on this topic.

A prolific writer concurrent with his clinical practice and administrative responsibilities, Dr. Mehler has penned nearly 500 scholarly pieces, including the seminal textbook in the field titled Medical Complications of Eating Disorders (John’s Hopkins University Press, fourth edition forthcoming in 2021). Dr. Mehler’s list of publications is extensive, totaling almost 500 articles spanning his 30+ years in the field of medical treatment of severe eating disorders.

Dr. Mehler was the recipient of the Academy of Eating Disorders 2012 Outstanding Clinician Award, has been recognized among the “Best Doctors in America” for the past 23 years in a row, and was voted the “Top Internal Medicine Physician in Denver” multiple times by 5280 Magazine.

In 2008, he received the Silver & Gold Award, an award given every three years to one alumnus of the University of Colorado and the Florence Sabin Award given to one citizen of Colorado annually for great contributions to healthcare in Colorado.


  • Thanks for pointing out that carbs would play a huge role in recovering from an eating disorder. I’m currently trying to look into eating disorder treatments because a close friend of mine has been talking to me about possible symptoms of anorexia. I better try to convince her to look for help as soon as possible before she becomes too in denial about her condition.

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