In a cruel twist, overeating can be deadly to someone with anorexia nervosa.
While family, friends and therapists may want to say, “Just eat!” restoring health to someone severely malnourished can be a very delicate matter, significantly complicated by the risk of the potentially fatal refeeding syndrome.
When an individual with anorexia nervosa begins to eat again, they face a host of issues that make food consumption and digestion challenging, including symptoms such as feeling full very quickly, constipation, bloating, swelling in the legs, changes in pulse and even gaining weight too quickly. The greatest danger, however, is posed by refeeding syndrome.
At base, refeeding syndrome is caused by adaptions the fasting or malnourished body makes to preserve function and muscle breakdown as much as possible. The impact of malnutrition affects every organ in the body, slowing down many basic biological functions, so the body simply does not work like it does in healthier individuals. The metabolic rate, for instance, may be 20% to 25% lower than in other individuals.
In addition, the body switches from using carbohydrates to using fat and protein for energy. As a result, blood levels of ketones rise and the liver reduces its production of glucose, which preserves muscle protein. On an intracellular basis, phosphate and other minerals become severely depleted, though serum levels may remain normal.1
When the body once again receives nutrition, it increases insulin production and reduces glucagon production. The insulin facilitates glycogen, fat and protein synthesis, which uses phosphate, magnesium and thiamine, and stimulates potassium absorption by the cells. The insulin boost dramatically increases uptake of phosphate, generating a sharp drop in intracellular and extracellular phosphate levels and disruption of nearly all cellular processes and physiological systems.
This disruption is central to refeeding syndrome, a metabolic complication that may occur in the first week or two after an individual who is severely malnourished begins to eat or receive parenteral or enteral nutrition. If an anorexic receives too many calories too quickly, they can develop dangerously low phosphate, magnesium, thiamine and potassium levels that can lead to serious cardiac, pulmonary, hematologic, neuromuscular, and neurological complications. Other complications may be triggered by abnormal sodium and fluid levels as well as changes in metabolism of glucose, protein and fats. The syndrome can also occur in individuals who don’t have eating disorders, but are malnourished for other reasons, such as individuals in the intensive care unit, cancer patients, or patients struggling to eat due to other medical reasons. In fact, the syndrome was first recognized in World War II when starved prisoners of war died after liberation when they first regained access to regular food.2
Individuals with anorexia nervosa consequently have a higher risk profile than other individuals because both the disorder and its recovery can be deadly. In fact, anorexia nervosa has the highest mortality rate of all mental illnesses at 10% to 20%.
To prevent refeeding syndrome from occurring, recovery programs should follow the guidelines issued in 2006 by the National Institute for Health and Clinical Excellence (NICE). First, they should identify patients at greatest risk, which includes those with body mass index below 16, those with minimal nutritional intake for 10 days or longer, and those that already have low levels of potassium, phosphate or magnesium. These individuals need the highest level of care and should not be treated in an outpatient setting as they require 24/7 nursing and medical care, monitoring of vital signs, daily lab work, and expert help to avoid refeeding syndrome.
Treatment centers should also order and monitor tests that include blood work with plasma electrolyte and glucose levels at intake and daily during the first 10 days. Recovering clients typically start on a low-calorie meal plan with supplemental vitamins and then titrate up. According to the NICE guidelines, refeeding should start at no more than 50% of energy requirements, but for many patients, the initial calorie load is significantly lower. Individuals with a BMI of 14 or less, for instance, should start on a maximum of 5 kcal/kg/24 hours with continuous heart monitoring and then increase gradually over the course of a week as tolerated.3
Refeeding syndrome is not the only hazard faced by an individual with anorexia nervosa who is starting to receive additional nourishment. Because many patients are not able to recognize the severity of their illness, they may rationalize that they are not that ill and do not need treatment. Many will continue to see themselves as fat or overweight even as their organs start to shut down from malnutrition. Extended extremely low calorie consumption will have also impaired brain function, making it difficult for patients to think clearly, make good decisions or focus.
Patients and often their family members must be helped to understand the impact of their eating disorder on their bodies and become engaged and motivated to pursue treatment. Family members may help to motivate them or support them in the often difficult decision to seek inpatient care, which may take several months.
Allowing enough time to recover is critical. Generally, anorexics in recovery can gain two to three pounds a week safely, so someone who is 50 pounds underweight may need treatment for more than four months. During treatment, some will continue to try to prevent weight gain, making support at meals and encouragement to complete meals critical. If that proves insufficient, facilities should have the capability to insert and manage nasogastric tubes or to have percutaneous endoscopic gastrostomy tubes inserted for direct delivery of nutrition, fluids, and medications to the stomach.
Many of the complications of treating patients with anorexia nervosa can be avoided by beginning treatment early in the course of the disease. Those with very low body weight can be very difficult to treat and have higher mortality rates than those who begin recovery earlier. Physicians, family members and others who suspect that an individual may have anorexia nervosa or another eating disorder should seek assistance and a positive diagnosis as soon as possible so that treatment can begin when it is most effective and before the eating disorder progresses far enough to seriously compromise the patient’s health.
1. Mehanna HM, Moledina J, Travis J. Refeeding syndrome: what it is, and how to prevent and treat it. BMJ. 2008 June 28;336(7659):1459-1498.
2. Crook MA, Hally V, Panteli JV. The Importance of the Refeeding Syndrome. Nutrition. 2001;17:632-637.
3. Manuel A, Maynard ND. Nutritional Support: Refeeding Syndrome. Student BMJ. 2009;9(4):b1567.