Are the biological changes of anorexia adaptations or dysfunctions?

Explanations attributing AN to biological dysfunction lack explanatory coherence. They must invoke multiple independent malfunctions to account for the syndrome. For example, Kaye and colleagues proposed that food refusal is caused by patients’ attempts to reduce serotonin levels, body image distortion and starvation denial are caused by a right hemisphere dysfunction, and that hyperactivity may be due to imbalance between motor area dopamine and serotonin. Such piece-by-piece explanations do not provide specific mechanisms and are silent on why these breakdowns happen together and normalize together with weight recovery.

In contrast, an evolutionary explanation does account for the broad array of AN phenomena, and it is supported by extensive evidence from multiple independent sources. The hypothesis that AN symptoms were selected in the past when starving foragers needed to migrate to find food accounts for AN’s puzzling psychological symptoms: The ability to ignore hunger and move energetically would have helped Pleistocene foragers leave a depleted home range. Self-deception about fat stores could have provided optimism to travel. Self-control, increased pain tolerance, cognitive rigidity, and the associated feature of perfectionism would have helped individuals persist on desperate journeys that few survived.

The hand of natural selection leaves fingerprints in the genes and in the phenotype. Nesse and Williams  have argued that natural selection is implicated when a genetic illness has significant incidence and multiple genetic changes affecting the same or overlapping functions. Adaptations look “designed” for a purpose and are often complex, efficient, modular, and universal across different cultures. The complex psychobiological changes of AN are difficult to explain except as the result of specific biochemical mechanisms resulting natural selection. The observations that AN is heritable, has a homogeneous presentation in individuals with only very low weight in common, and symptoms that remit with weight gain all strongly suggest that the symptoms are an evolved response to starvation.

3 thoughts on “Are the biological changes of anorexia adaptations or dysfunctions?

  1. yes yes yes yes yes not sure (edit?) yes yes yes yes yes yes

    not sure = “Self-deception about fat stores could have provided optimism to travel”. I think you mean self-deception/obliviousness about very thin/malnourished/depleting body rather than about fat stores spcifically. I think the main reason someone with an ED pays so much attention to fat stores is because of the cultural labeling and vilification of fat, so without that cultural influence they may not pay that specifically any attention, but more like – (with the ‘body dismorphia’ as they call it medically) they would be oblivious about the wasting thin body ?

    edit? = “Self-deception about body wasting could have provided optimism to travel”

  2. Also in case you are unaware, the underweight mindset which results in ‘anorexia’ is proposed to be the same mindset which results in ‘bulimia’/’orthorexia’/etc etc etc (and before I knew it was proposed, I felt like I knew that, as in my personal experience I easily switched between them and to me they all came from the same root of thinking patterns). I don’t know if you are aware of that but it might mean you want to change the subject from anorexia to restrictive eating disorders, or maybe if it’s too wordy list in brackets in the title “(and other RED)”, or alternatively leave it for another blog post to explain that the root thinking pattern of REDs is the same and the variations are different resultant behaviors from the same mindset, with different cultural influences.

    (if you would like to know the exact process of thinking in my mind, = a thought comes to mind, and is assumed/’stuck’ and compulsively/repetitively continued. That would be an advantageous adaption previously for hoarding/gathering/eating food, along with the other changes eg restlessness/need to move around, because it means a thought of finding food comes to mind, gets stuck there, and stays until the subject finds/gathers/eats it (roughly, may be slightly different), then this process gets compulsively/repetitively continued until they regain the weight. With cultural influences nowadays the mindset can assume/get stuck on lots of things eg reasons not to eat, resulting in RED ~(for me personally I recovered naturally from my underweight position a few times in my childhood without realizing it eg Whilst I was very young I was oblivious to the idea that I should restrict intake in any way at a time when I became ill, I naturally repetitively ate more and regained the weight eg2 I started to develop a RED but was then told by my father that I should be eating lots as it was natural for a young boy and needed it all for growing (must have been a bit skinny), at which point the stuck thought was to eat, and I naturally regained weight by repetitively eating as much as possible at each meal with the idea that I needed it all for growing. In both examples (there must have been more subtle examples at a very young age eg3 snacking on vegetables was something my dad said was good so instead of snacking to hunger, snacked on vegetables then somehow that also resolved naturally, but the first 2 in particular are the ones that stick out) the repetitive behavior went away and the mindset and all the repetitive behaviors became dormant until I became underweight again. Inevitably later on I became underweight again and other stuck thoughts taken from society caused me not to gain the weight back)

    If you are already aware of what I am saying great. If not I don’t expect you to take my word for it even though I am 99.999999% (human error) certain, and my wording might not describe it as precisely/concisely/effectively as it could be. I hope that my account can help , I would like to see an improvement in RED (restrictive eating disorder) diagnostic and treatment. Your work is very encouraging and refreshing. Thank you

  3. Hi Pat, Thank you for writing. Yes, I am talking about the self-deception that leads people to believe they are well when they are seriously underweight. You are right that I mean “self-deception/obliviousness about very thin/malnourished/depleting body rather than about fat stores specifically.” Thank you for clarifying that.

    Best regards,

    Shan G

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