Refeeding Syndrome in Severe Eating Disorders

Increasing caloric intake quickly in individuals with anorexia nervosa and ARFID without frequent monitoring of blood tests and electrolyte replenishment can lead to a life-threatening complication marked by a shift in fluids and electrolytes within the body.

For severely underweight patients with anorexia nervosa and ARFID, nutritional rehabilitation is a primary and essential intervention. During the process of refeeding, food is reintroduced based on the metabolic needs of the patient in order to reverse the serious medical consequences of progressive starvation and malnourishment and effectuate consistent weight gain. However, it is critical that patients be closely monitored by experienced medical professionals during this initial phase of treatment to prevent—or address—a potentially fatal complication known as refeeding syndrome.

Refeeding syndrome is characterized by a dangerous shift in fluids and electrolytes within the body, and occurs in a small subset of patients when calories are introduced quickly and lab tests are not checked and abnormalities treated. When the body is starved or severely malnourished, the heart muscle may atrophy causing diminished cardiac output, and 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. When food is reintroduced during the refeeding process, there is an abrupt shift from fat and muscle metabolism back to carbohydrate metabolism, increasing the body’s uptake of phosphorus and other key electrolytes into newly developed cells and decreasing levels of these electrolytes in the blood. This sudden change in the balance of electrolytes causes the atrophied heart to work harder to manage a higher blood volume, which can cause irregular heartbeat, muscle damage, weakness, seizures and even death.

Along with low levels of phosphorus in the blood, another symptom of refeeding syndrome is edema, or swelling in the lower extremities. During refeeding, the body secretes insulin and the kidneys retain salt and water. This weight gain and visible changes in body size associated with severe water retention can be particularly distressing for patients that fear weight gain or suffer from body image concerns and/or body dysmorphia. Edema will generally resolve with continued management of refeeding.

This life-threatening complication of caloric initiation is usually preventable when refeeding is administered by eating disorder experts. However, most 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 an inpatient medical setting capable of treating the most serious eating disorders.