Hypermetabolism in Anorexia Nervosa

Weight restoration is a crucial component of anorexia nervosa treatment. It is a challenging process for a multitude of reasons. Adding to the complexity and the challenge is the fact that during weight restoration, individuals with anorexia nervosa tend to require increasingly more calories to maintain the same rate of weight gain.

That is, individuals need to continually increase their caloric intake, in steps, sometimes upwards of 100 calories (technically, kilocalories) per kilogram per day, to continue gaining weight. For instance, an individual weighing 45 kg may need to eat 4,500+ calories to continue gaining 1-1.5kg (2.2-3.3lbs) a week. Indeed, studies have found that standard resting energy expenditure (REE) equations tend to overestimate caloric needs at the beginning of refeeding but underestimate them in the later stages (Forman-Hoffmann et al. 2006; Krahn et al., 1993).

After achieving a healthy weight, individuals recovering from anorexia nervosa still typically … Continue reading →

CCK and the "Hunger Trap" in Anorexia Nervosa (Why Gaining Weight is Hard)

Cholecystokinin (CCK) is a digestive hormone that stimulates fat and protein digestion, and promotes the feeling of satiety. CCK is released after food consumption to promote digestion (by releasing digestive enzymes from the pancreas and stimulating bile secretion). In rats and monkeys, injection of CCK induces satiety, though it seems (from what I’ve skimmed), the extent to which CCK regulates food intake in humans is not well-established. Previous research on the role of CCK in anorexia nervosa (AN) has found conflicting results, in part because of methodological issues related to measuring levels of CCK. In a recent study, Cuntz and colleagues (2013, freely available online), having developed a better assay for measuring CCK, wanted to clarify its role in AN patients.

The authors had the following goals and hypotheses (I omitted one):

  • Objective 1: Compare CCK levels between AN patients and healthy controls before and after a meal
  • Objective
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Avoiding Refeeding Syndrome in Anorexia Nervosa

Refeeding syndrome (RS) is a rare but potentially fatal condition that can occur during refeeding of severely malnourished individuals (such as anorexia nervosa patients). After prolonged starvation, the body begins to use  fat and protein to produce energy because there are not enough carbohydrates. Upon refeeding, there’s a surge of insulin (because of the ingested carbohydrates) and a sudden shift from fat to carbohydrate metabolism. This sudden shift can lead to a whole set of problems that characterize the refeeding syndrome.

For example, one of the key features of RS is hypophosphotemia: abnormally low levels of phosphate in the blood. This occurs primarily because the insulin surge during food ingestion leads to a cellular uptake of phosphate. Phosphate is a very important molecule and its dysregulation affects almost every system in the body and can lead to “rhabdomyolysis, leucocyte dysfunction, respiratory failure, cardiac failure, hypotension, arrhythmias, seizures, coma, and … Continue reading →