 (considerable weight loss in genetically susceptible individuals) and the mechanisms by which the cause operates (via a critical fall in leptin that is exacerbated by the presence of estrogen); it explains quantitative features (sex ratio and epidemiology); it accounts for more AN phenomena than other AN theories (why starving people eat little, move restlessly and hallucinate fat stores); it reveals the unity that underlies the apparent diversity of AN (the core symptoms have remained the same while explanations differed); and, it points toward more fruitful research questions in the psychology, genetics and neuroscience of AN, and toward more effective interventions. Thus, the AFFH meets the criteria for a sound scientific explanation, providing precision, scope, simplicity, prediction, and usefulness (65).
In the Paleolithic some behavioral mechanism probably helped anorectic tribal members to eat when food was once again plentiful. If the traditions of extant nomadic tribes are an indication, this mechanism involved social support. When more food becomes available after a shortage, traditional societies celebrate with a feast (66). Refusing such food would be a profound breech of social norms and insult the giver. Humans are deeply social (67) and AN is probably most easily “switched off” with social support. For a starving tribe an anorectic’s energy, optimism, and grandiosity could inspire them to undertake an arduous journey, much as the anorectic Joan of Arc inspired soldiers to march with her (68). When they reached better lands, bands would in turn have helped their heroic scouts recover through eating and weight restoration.
People with AN must eat although eating fills them with shame, regret and dread; they get full quickly, and they cannot see how thin they are. They must reduce exercising while the anorexic voice castigates them as lazy and weak. Today the two most popular therapies for AN — Cognitive Behavior Therapy for eating disorders, which focuses on changing patients’ “fears of getting fat,” and Interpersonal Psycho-Therapy, which focuses on relationship problems (5) — did less well in a randomized clinical trial than a control group. At a 6-year follow-up the theory-based therapies were still no better (69).
Preliminary data indicate that our evolutionary neurobiological explanation improves recovery. Explaining that compulsions to move and fear of feeding were evolutionary adaptations that once saved their ancestors helps patients resist them (70). This also improves patients’ motivation and confidence that they can recover and helps clinicians and loved ones empathize and support them in recovering their weight.
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