What Is Refeeding Syndrome? Everything You Need to Know
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Malnutrition can occur for many reasons — like food insecurity, for instance, or your body being unable to properly absorb food. Another common cause is an eating disorder that involves the restriction of calories or lack of nutritional balance. In eating disorder treatment, addressing malnutrition is the first priority. But that doesn’t mean just jumping right into three square meals a day.

Reintroducing food into your system after you’ve gone an extensive amount of time eating very little isn’t always easy, and going about it in the wrong way can result in various issues. One of the most common issues that can stem from this process is refeeding syndrome.

Read on to learn what refeeding syndrome is, what it does to your body, and how to avoid it.

The basics of refeeding syndrome

Nutritional rehabilitation is a key part of treatment for eating disorders like anorexia nervosa and bulimia nervosa, helping patients to achieve weight restoration and address nutritional deficiencies. It involves introducing calories to the body, either by eating and drinking or through a feeding tube.

Refeeding syndrome refers to a dangerous complication that can occur during nutritional rehabilitation if it’s not done correctly. When the body starts to ingest calories after a long period of restriction, it can cause a metabolic disturbance that could lead to potentially life-threatening shifts in the body’s fluid and electrolytes, most commonly potassium, phosphorus and magnesium, levels. The severity of refeeding syndrome can vary from person to person; one recent study showed that approximately 22% of adolescents with anorexia experienced mild symptoms during the refeeding process, while 6% experienced severe symptoms.

There are many medical issues that can be symptoms of refeeding syndrome, including:

  • Muscle weakness
  • Increased heart rate
  • Heart weakness (cardiomyopathy)
  • Low blood pressure
  • Difficulty breathing
  • Nausea, vomiting, loss of appetite
  • Double vision
  • Fatigue
  • Trouble swallowing
  • Fluid retention/fluid in your lungs
  • Seizures
  • Low blood pressure
  • Coma
  • Muscle spasms and tremors
  • Nausea and vomiting
  • Heart arrhythmia
  • Loss of appetite
  • Coma

Patients may have a higher risk of experiencing refeeding syndrome if their body mass index is lower than 16 or if they’ve lost 10% or more of their body weight in the last three to six months or have had severe restriction for the past 7 days.

What happens to the body during refeeding syndrome?

Refeeding syndrome is caused by a shift in fluid and electrolytes that can have a domino effect throughout your body and cause severe symptoms, including death.

These fluid and electrolyte shifts are related to low stores of electrolytes, most often, potassium, phosphorus and magnesium. Electrolytes are minerals that play a vital role in many of your body’s functions. When someone is undergoing the refeeding process — which we also refer to as nutritional rehabilitation — their body needs these electrolytes to metabolize the food they are eating. This causes a depletion of electrolytes, which, in turn, causes the fluid shifts that often accompany these electrolyte deficiencies. All of this then causes the multiple symptoms that you often see in refeeding syndrome.

The most common example of a dangerous imbalance that can occur in refeeding syndrome is decreased phosphorus levels. Phosphorus is important for many things in the body, including energy storage and regulating how hemoglobin carries oxygen throughout the body. Even small decreases in phosphorus can affect our organs, leading to potentially serious health risks such as muscle weakness, heart weakness, difficulty breathing, and coma.

Another potential effect of refeeding syndrome is a deficiency of vitamin B1, or thiamine. This results from carbohydrates being quickly used up in glycolysis, or the process of breaking down sugars in the body. This deficiency can lead to severe neurologic symptoms like amnesia, unsteady gait (ataxia), and delirium.

Prevention and treatment of refeeding syndrome

While there is no way to 100% guarantee that a person won’t experience refeeding syndrome, it’s possible to significantly minimize risk. The key to doing so is adapting the refeeding process to a person’s particular physical condition, BMI, and vitamin deficiencies. Monitoring the process and making electrolyte adjustments when necessary can also go a long way in reducing the risk of any severe complications.

Refeeding syndrome can sometimes mean that calories are being introduced to the body too quickly. In these cases, patients need to work closely with a physician and dietitian trained in treating eating disorders to come up with a game plan for gradually ramping up calories. This may mean that weight restoration goes a little more slowly at first, but it’s an important precaution to take if someone is experiencing severe symptoms.

If you or your loved one do start to experience symptoms of refeeding syndrome, alert your medical team immediately. They’ll determine the best way to proceed, which may include slowing down the refeeding process as well as electrolyte replacement and closely monitoring fluids and electrolyte levels.

Equip can help reduce the risk of refeeding syndrome

Weight restoration is one of the first steps for most people working to recover from severe malnutrition, and an essential component of lasting recovery. At Equip, you have a dedicated team of professionals to help you throughout your recovery journey, including a medical provider and dietitian, both of whom are well trained in working with people who have eating disorders. Together, they’ll assess any risk of refeeding syndrome and come up with a plan that minimizes risk and closely monitors progress and any complications..

With the correct treatment, you can safely reintroduce your body to the nutrients it needs to properly function and reach a weight that allows you to live a full, eating disorder-free life. Get in touch with our team today for more information or to schedule a free consultation.

About Maria La Via, MD

Dr. Maria La Via, a Supervising Child and Adolescent Psychiatrist at Equip, is an experienced child, adolescent and adult psychiatrist focusing on working with individuals struggling with an eating disorder. Dr. La Via has a demonstrated history of working across various healthcare settings, including inpatient, residential, partial hospitalization, intensive outpatient, and outpatient care, as well as in clinical research. Skilled in Clinical Supervision, Psychological Assessment, Psychopharmacology, Cognitive Behavioral Therapy (CBT), and Family Based Treatment, Dr. La Via is also an Adjunct Faculty member at the University of North Carolina at Chapel Hill.


1. Mehler, Philip. “Anorexia Nervosa in Adults and Adolescents: The Refeeding Syndrome.” UptoDate. Oct. 2023. https://www.uptodate.com/contents/anorexia-nervosa-in-adults-and-adolescents-the-refeeding-syndrome#:~:text=A%20retrospective%20study%20of%20adolescents,in%2022%20percent%20%5B2%5D.

Kate Willsky
Senior Manager, Content
Clinically reviewed by:
Maria La Via, MD
Director of Psychiatry, Equip
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