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Small Feedings and Current Nutrition Practices in Anorexia Nervosa

During this decade there has been a general change in the manner with which nutritional rehabilitation is prescribed for patients with anorexia nervosa (AN).

In the past, daily caloric prescriptions for initial weight restoration were in the 5- to 10-kcal/kg range.  However, more recent research has shown that higher dietary prescriptions are associated with a reduced length of in-hospital stay, and with no increased risk of electrolyte disturbances or other adverse reactions.  In fact, the risk of refeeding hypophosphatemia has been demonstrated to increase with the severity of nadir weight rather than with the amount of calories delivered. Thus, the lower the initial percentage of ideal body weight (IBW), the greater need for vigilance in checking serum phosphate levels.

Taking a more aggressive approach to refeeding

A weekly inpatient-residential weight gain goal of 1.5 kg to 1.8 kg is being accomplished through a more aggressive approach to refeeding.  Initial meal plans now start at 1400 to 1800 kcal/day, with increases of 300 to 400 kcal/day every 3 to 4 days, until a consistent weight gain of 0.2 to 0.25 kg/day is noted. No maximum calorie levels are applied, as dietary prescriptions are individualized to support ongoing weight gain toward ideal body weight. Also, the ideal macronutrient source of energy (calories) is still not entirely proven for this type of severe malnutrition, but a typical composition is 40% carbohydrate, 40% protein, and 20% energy from fat.

Many dietitians agree that it is helpful to allow patients to choose the form their calories come in while encouraging solid and broad varieties of food for the majority of meals when medically appropriate, but with a lower threshold to revert to liquid supplements and enteral feeds via a nasogastric (NG) tube if oral intake is inadequate.  This is because of a new focus in treating AN, avoidance of “underfeeding.” An ill-defined, passive “wait and see approach” to refeeding AN patients is no longer acceptable.

Comorbidities can affect the nutrition prescribed

Comorbidities such as superior mesenteric artery syndrome (SMA), found with increased frequency as the percentage IBW is lower, and dysphagia, can affect the refeeding regimen or diet prescription, but not the starting calorie prescription.  The severity of SMA determines how a patient’s nourishment is administered. The utilization of the gut is always preferred; if a patient has complete SMA, diagnosed by abdominal CT scan, the recommendation would be to refeed with 100% liquid formula administered via an NG or perhaps a nasojejunal (NJ) tube, placed distal to the obstruction. If the patient has partial SMA, the diet is typically formulated as a pureed or soft diet. Normally, the diet can then be advanced slowly after only a 5- to 10-lb weight gain, as the SMA obstruction resolves.

Dysphagia can also occur in more severely malnourished patients with AN due to pharyngeal muscle atrophy, which places these patients at risk for aspirating liquids and solids.  If aspiration is confirmed by a speech language pathologist, consistent modifications in food and/or formulas should be made until weight restoration normalizes swallowing function.   It is important to note that with both of these medical complications of AN as well as with others such as gastroparesis, diarrhea, and diabetes, increased intensity of nutrition education and counseling by an informed registered dietitian (RD), are imperative to promote patient compliance as enteral feedings, supplements, or modified textures may create an extra challenge to patient compliance.

The benefits of nutrition intervention

According to Ozier and Henry, “It is the position of the American Dietetic Association (now the Academy of Nutrition and Dietetics) that nutrition intervention, including nutrition counseling by a registered dietitian, is an essential component of the team treatment of patients with AN, bulimia nervosa, and other eating disorders during assessment and treatment across the continuum of care” (Ozier and Henry, 2011).

Registered dietitians act as an integral member of the team in the treatment of eating disorders at all levels of care.  A dietitian who specializes in the treatment of eating disorders assists the multidisciplinary team, as well as the patient, in many ways, first by assessing calorie requirements based on typical metabolic needs and weight gain goals for AN patients. Next, dietitians use medical nutrition therapy to treat a patient’s medical complications from malnutrition and weight loss, such as gastroparesis, SMA syndrome, or malabsorption. Finally, when necessary, the dietitian can prescribe enteral and parenteral nutrition support.

The dietitian can also help decipher a patient’s readiness for change by using motivational interviewing.  In addition, the dietitian can help the patient try new types of foods, whether by adding a macronutrient the patient is fearful of or adding a specific food, such as a dessert, into the patient’s diet.  The latter is especially relevant for those with Avoidant Restrictive Food Intake Disorder (ARFID). Dietitians can also assist patients in weaning off of enteral nutrition support while increasing oral nutrition and by challenging patients to make healthy, productive choices towards recovery by setting boundaries around mealtime behaviors, food flexibility and meal completion expectations to ensure adequate nutrient intake and weight gain trajectory.

It is also vital that the dietitian builds a productive rapport with his/her patient by working in an open and honest way, guiding a patient’s choices away from what their eating disorder wants and individualizing their care as much as possible to build a foundation of trust and respect.  Dietitians are often viewed as an “enemy” or an “ally” to a patient as they upset the eating disorder by challenging a patient to interrupt behaviors while they assist in nourishing the patient, which helps him or her feel stronger and healthier.

Reminding a patient about the positive effects of renourishment, such as sharper cognitive skills, improvement in their physical condition, and being able to more successfully engage with loved ones, can help a patient to feel motivated, continue to make progress in treatment, and begin to place trust in their treatment team to achieve a sustained and full recovery.