Calorie Restriction, Anorexia Nervosa, and Memory Gaps

This post has been translated into Russian by Polina here.

I have often heard anorexia nervosa sufferers complain of “memory gaps,” particularly during the times they were really sick. As if they weren’t really there.  It can be scary and unnerving, to say the least. A few months ago, a Tumblr user asked me about this:

Hi Tetyana, I’m not sure if this is merely based on my own subjective experience of if there is any grounding at all, but I was wondering if there could perhaps be a link between EDs and a sort of memory loss. It’s hard to describe but I definitely seem to have huge “gaps” in my memory of during that time, as if I selectively block things out. I have limited inaccurate knowledge with regards to memory on a molecular/neurological basis so I do not know if there’s anything there. Perhaps with calorie restriction in anorexia nervosa there is simply not enough “energy” for memory to function adequately? I don’t know whether there is a link here and how far a sort of “memory loss” is experienced by those with anorexia and other EDS and if so, why.

I researched the question a bit myself and what was meant to be a short responses turned into a 1,000+ word answer.

In this post I’ll expand on my answer, and so it will be different from what I usually write. It won’t be an in-depth analysis of one or two studies. Instead, I’ll guide you through my thought process in answering this question and what I found during my search.

Importantly, I am not expert on this topic and I have not done a thorough search, which is to say: this is not comprehensive and your ideas/thoughts are always welcome.

When I first read the question, I thought, assuming this is something that is true and replicable among many with eating disorders (or just anorexia nervosa), the phenomena might be due to deficits with learning OR memory OR recall (among other things). Each of these are separate things and can be teased apart experimentally (Well, at least in rats and mice, I don’t know much about human research on learning and memory.)

A lot of things immediately sprung to my mind about what could be happening. Maybe it is lack of energy (glucose) during the acute AN phase for actual cellular function, or maybe it is due to impairment in hippocampal neurogenesis (the hippocampus is crucial for learning and memory), or maybe it is a trait (something that existed before the onset of the ED), or maybe it is due to a preoccupation with food/weight which leaves little “mental space” for other learning and memory to occur? A lot of possibilities, and those are just some that came to mind.

I figured that a good way to “test” the idea that learning and/or memory impairments might be due to lack of energy (calorie restriction) would be research the findings in the calorie restriction (CR) field. CR has been linked to longevity and there are accumulating studies in primates on the effects of CR not only on longevity but also on cognitive function.

I found one study in humans that suggested that a CR diet actually IMPROVED memory. (Although the mean age of the sample was 60.)

They concluded,

This interventional trial demonstrates beneficial effects of caloric restriction on memory performance in healthy elderly subjects. Mechanisms underlying this improvement might include higher synaptic plasticity and stimulation of neurofacilitatory pathways in the brain because of improved insulin sensitivity and reduced inflammatory activity. Our study may help to generate novel prevention strategies to maintain cognitive functions into old age.

Then I found another (small) study, a 6-month randomized controlled trial, that showed CR did not have any negative effects on learning, memory or cognition.

This randomized controlled trial suggests that calorie restriction/dieting was not associated with a consistent pattern of cognitive impairment. These conclusions must be interpreted in the context of study limitations, namely small sample size and limited statistical power. Previous reports of cognitive impairment might reflect sampling biases or information processing biases.

So, if this is true, it suggests that calorie restriction and energy deficit alone do not play a huge rule of learning/memory deficits in AN. Of course, this is under the assumption that the “memory gaps” experienced by the OP, and by others I have talked to is linked to anorexia nervosa. That may not be the case.

Next I thought: what are the effects of dieting as opposed to calorie restriction on cognitive function? There have been a bunch of studies (mostly by the same group, though) that have shown that self-initiated dieting has negative impacts on cognitive function (such as learning and memory):

Vreugdenburg, Bryan & Kemps (2003) found that, compared to non-dieting controls, individuals who were dieting performed worse on cognitive tasks. They found that the higher levels of preoccupying cognitions in the dieters, the worse the functioning of the “central executive.” That’s stuff like learning, memory, attention, reasoning, and task switching.

Kemps, Tiggemann, & Marshall (2005) also found that dieters, compared to controls, performed poorly on various tasks testing working memory and other cognitive functions. They suggested that the preoccupying thoughts about food, weight, and body shape were responsible for the decrease in cognitive functions. They hypothesized that preoccupation with these issues (dieting, food, weight, shape) take up a lot of “mental space” and leave little for other tasks. The same group reported a similar finding in another study, too.

They argued:

These cognitive deficits are due to psychological mechanisms underlying the process of being on a diet rather than to physiological consequences of weight loss. For example, experimentally manipulated food deprivation for 24 h (Green, Elliman, & Rogers, 1995) or even several months (Kretsch, Green, Fong, Elliman, & Johhson, 1997) does not impair cognition. More specifically, the act of dieting has been linked to an increased preoccupation with thoughts about food, eating, weight and body shape (Jones & Rogers, 2003; Rogers & Green, 1993). Such preoccupying cognitions are thought to reduce the amount of working memory capacity available for cognitive task performance (Green, Elliman, & Rogers, 1997).

It is important to keep in mind that the above studies compared dieters with non-dieters, NOT individuals with anorexia nervosa to non-dieters or dieters.

So what about studies on learning and memory in anorexia nervosa patients?

There was a study published in 2010 by Nikendei and colleagues that found impaired memory performance in patients ill with AN but they also found that these deficits persisted after weight-restoration. They concluded that “the findings suggest that impaired memory performance is either a stable trait characteristic or a scar effect of chronic starvation that may play a role in the development and/or persistence of the disorder.”

Personally, I don’t buy the stable trait idea. I’m not even sure I buy the scar effect–though I would suppose that would depend on the illness severity/duration versus length of remission, maybe.

In their introduction, Nikendei et al reviewed the contradictory findings with regards to learning and memory in AN:

However, studies that have focused on various facets of general memory performance have shown a range of contradictory results. Some authors have reported immediate (Hamsher et al. 1981; Jones et al. 1991; Green et al. 1996; Kingston et al. 1996; Mathias & Kent, 1998; Bayless et al. 2002; Moser et al. 2003) and delayed (Jones et al. 1991; Mathias & Kent, 1998; Bayless et al. 2002) verbal recall deficits in acute AN patients whereas others have revealed normal (Szmukler et al. 1992; Mathias & Kent, 1998; Lauer et al. 1999; Moser et al. 2003; Connan et al. 2006; Nandrino et al. 2006; Bosanac et al. 2007) or even superior (Hatch et al. 2010) immediate verbal recall and normal delayed verbal recall (Kingston et al. 1996; Mathias & Kent, 1998; Nandrino et al. 2006; Bosanac et al. 2007; Hatch et al. 2010).

Nikenei et al. pointed out that imaging studies (Wagner et al., 2007) do not suggest there are any structural changes in the hippocampus (which, as I mentioned above, is important for learning and memory, and it is also one of two brain regions in adults where neurogenesis (the birth of new neurons) occurs). But of course, deficits can easily occur on a level that’s undetectable by conventional brain imaging techniques.

So, there’s no definitive answer (as far as I can tell right now), but it might be that AN (or eating disorder) related obsessions “take up mental space” and interfere with cognitive functions. This also makes sense give the findings which have suggested that patients with AN have a “memory bias” toward ED-related things (food, weight, calories), which I’m sure is something that all readers who have experienced an eating disorder can attest to. (For more on that, see: Sebastian et al. 1996; Hermans et al. 1998; Williamson et al. 1999; Pietrowsky et al. 2002; Lee & Shafran, 2004; Suslow et al. 2004; Nikendei et al. 2008; Tekcan et al. 2008.)

Readers, what do you think? Have you experienced these “memory gaps”? What else, that I’ve overlooked, might be helpful in answering this question? Or is there an answer (perhaps a study) that I missed in my search?



Kemps E, Tiggemann M, & Marshall K (2005). Relationship between dieting to lose weight and the functioning of the central executive. Appetite, 45 (3), 287-94 PMID: 16126305

Martin, C., Anton, S., Han, H., York-Crowe, E., Redman, L., Ravussin, E., & Williamson, D. (2007). Examination of Cognitive Function During Six Months of Calorie Restriction: Results of a Randomized Controlled Trial Rejuvenation Research, 10 (2), 179-190 DOI: 10.1089/rej.2006.0502

Nikendei C, Funiok C, Pfüller U, Zastrow A, Aschenbrenner S, Weisbrod M, Herzog W, & Friederich HC (2011). Memory performance in acute and weight-restored anorexia nervosa patients. Psychological medicine, 41 (4), 829-38 PMID: 20529417

Vreugdenburg L, Bryan J, & Kemps E (2003). The effect of self-initiated weight-loss dieting on working memory: the role of preoccupying cognitions. Appetite, 41 (3), 291-300 PMID: 14637328

Witte AV, Fobker M, Gellner R, Knecht S, & Flöel A (2009). Caloric restriction improves memory in elderly humans. Proceedings of the National Academy of Sciences of the United States of America, 106 (4), 1255-60 PMID: 19171901


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Tetyana is the creator and manager of the blog. She has an Honours BSc in Neuroscience and an MSc in Medical Science. She can be reached at tetyana[at]scienceofeds[dot]org.


  1. Hi Tetyana, thank you for this!
    I definitely have experienced huge cognitive impairments throughout my ED years, but also, experienced the selective superior recall of food related/calorie related sujects.. it always seemed ironic to me!

    Some brief thoughts (since it’s the middle of the night and I am tired)
    – I wonder if the memory problems many people with AN have are actually trauma related? Trauma does impair memory and cognition and many people with ED also have a history of trauma.
    – I wonder if the increased memory that CR studies show don’t seem to translate for many with AN because perhaps these ‘good’ results come to a peak, and then after that point, CR begins to inhibit memory ability. Definitely those with AN usually have a far more profound restriction of calories and nutrients than those just following a long term CR regimen.
    – I wouldn’t neccessarily compare AN with dieters, simply because AN is a mental illness, it could be far more different than a mentally healthy person going on a diet. People with other mental illnesses often experience problems with their cognitions and memory, without dieting or restricting – so I would assume there is more at play for those with an ED than the effects of starvation alone?

    Thank you for making me ponder, yet again, the mystery that ED is – it never is as straightforward as it seems.

    • I’ve always tended towards CR as the explanation for my memory gaps, since (especially in this past relapse) I don’t always have the obsessive food thoughts. But your comment about trauma got me thinking:
      What if it isn’t that people with EDs have trauma history and therefore have memory gaps, but that the ED itself is traumatic? I think we could all agree that being really in the illness indescribably horrible … shouldn’t that count as trauma?
      Just something that you got me thinking about — thank you!

      • Good point. I wouldn’t consider my ED traumatic, per se, but I do know that many of the things people experienced during their ED really was traumatic or them (often associated with being so physically compromised, or treatment).

        • something interesting – maybe the ED is traumatic to us without us realising it. It’s certainly traumatic physiologically.
          My psychologist told me the other day about how she had been in an emergency landing on the flight home from a conference. She doesn’t mind flying at all, and was ‘cool as a cucumber’ during the very rough landing. However for the next couple of weeks she started waking up in the night thinking she had heard a loud plane propeller noise from some plane flying over her house(she had been in a light plane) until she remembered there is no flight path over or near her house. She realised her mind was replaying a noise from the emergency landing – even though she had been ‘fine’ her body had still subconsciously registered that it was in danger and that a trauma was occuring. She was experiencing flashbacks of a background noise she hadn’t even taken notice of when it happened. I found this really fascinating!

          • Wow, yeah, that is interesting.

            I’m not sure it can be traumatic without us realizing it, though. Because your psychologist clearly realizing it was traumatic in retrospect — she is having flashbacks — despite not thinking it would be and feeling fine in the moment. But, if you don’t have flashbacks or fears or some kind of a sign that it was traumatic despite you not thinking it should be or that it was in the moment, well, then I doubt it is traumatic. You know what I mean?

            It is interesting, but I wonder how much that has to do with our self-image and how we perceive our ideal self vs. the reality. (We are more vulnerable than we’d like to think we are, I think.)

    • Hi Fiona,

      All of those are excellent points!! I had not thought of any of them before reading your comment!

      The trauma one is interesting and I wonder if that could play a role, at the same time, what about people who have not experienced trauma? I’m not sure, on a biological level, how trauma affects memory (not that it does, just that I don’t know the neurobiology or what we know if it) so it is hard for me to comment.

      Good point on CR! CR can be as restrictive as AN for some (I know some who ate at their worst similar to what individuals on CR eat), BUT they are focused on eating very nutrition rich foods, so while calorically it is low, the quality of the food is undoubtedly, on the whole, better. The long term component is another interesting point.

      Interesting point on dieting. I don’t want to compare dieting with EDs in other aspects (like, for example, the motivation to lose weight or the underlying causal factors) but, on a behavioural level, the obsession/preoccupation with food can have a lot of similarities and I think it is a useful ‘control’ for some of these studies.

      Likewise–thanks for making me ponder some of this, too! Your comments are always thoughtful and intelligent. I really appreciate them.

      • I wonder if there are any studies that follow people who go on ‘diets’ and how they fare long term psychologically? I know for many, dieting is a pathway to an eating disorder. If two people with similar lives, ages, histories, weights, health etc – both go on the same diet and one person develops an eating disorder, what was it that was different for that person, or about that person?
        Probably that is where being predisposed might come in, or having something like OCD-type patterns?

  2. “it might be that AN (or eating disorder) related obsessions “take up mental space” and interfere with cognitive functions. This also makes sense give the findings which have suggested that patients with AN have a “memory bias” toward ED-related things (food, weight, calories), which I’m sure is something that all readers who have experienced an eating disorder can attest to”. –> I’m with you there! I didn’t really experience any cognitive deficits that I’m aware of (I was still pretty good at memorizing a ridiculous amount of information for exams), but I didn’t think about much else besides food and studying. I also wonder about “state-dependent” memory. My husband often reminds me of how anxious and irritable I used to be and how much I’ve been improving, but I have a hard time remembering just how bad I was.

    • I agree. The state-dependent memory is an interesting point. I’m not sure if it is that or if it is just that we often, in retrospect, minimize (or emphasize) various experiences?

  3. I forgot to say, I could at times think of nothing BUT food/weight/calories. I could not read my beloved novels, I could not study, but I could pore over food magazines, recipe books, supermarket catalogs and calorie guides. I can only think that it was starvation. I was so starved for food, that in it’s quest for survival my brain refused to process anything non-survival related – food being top of it’s list of priorities.

    • Yes!! I think many people would relate to that, but to your point about dieters, I think some (perhaps many) would relate, too.

      • Yes, it seems to come with starvation and/or deprivation. It’s a pity I couldn’t have that amount of focus and recall for school-related stuff!

        Also I think how our memory is affected differs for all of us. I was forced out of study pretty early on, my thinking was so badly affected that I would often feel like the world was speaking/writing/happening in a different language. But a friend of mine with SEAN completed her honours thesis in a genetic microbiology research subject with first class honours while emaciated and medically very unwell. I have other friends who also excel in their school work despite being very unwell. I have met other people who have been unable to study at all, but I actually started to think it must be something to do with -me- and that I was just lazy or dumb, because everyone else I knew seemed to get on fine.

        • Um, well, I don’t know you IRL of course, but you are NOT dumb. You always preface your comments with the fact that you are tried/late at night/etc to excuse what I think you think are sometimes incoherent thoughts, but you always have SUCH intelligent and thoughtful and easy to follow comments!! Seriously.

          Yeah, people differ. I know some people who feel faint/like crap from just restricting a little whereas I ran my PR for a half-marathon and a 30k race at a very low weight, undereating and not training. I am eating way more now, and to be honest, feel absolutely NO difference in cognitive functions at all, and I’m at a normal weight. It didn’t have much effect on me. All it did was affect my bones and such, and of course, I spent more time *thinking* about food/calories but otherwise, I was fine. Weird, eh. It is very interesting.

          • Your comment got me thinking…I know doctors are always saying to underweight anorexics, “your weight is too low, you can’t think clearly,” but is there really evidence to support this assertion? I was certainly told that, but at my lowest weight there’s nothing that I wouldn’t have also thought at a much higher weight. (Obviously, obsession with food, etc can change but I wouldn’t call that “not thinking clearly”).

          • Yeah, I think it depends and varies on a person-to-person basis. I am weary of those comments when they are used in a dismissive way–as if to discard or dismiss a patient’s concerns. I find that very problematic. I also find any absolutist assertions very problematic (that ALL AN patients can’t think clearly at a certain BMI or after a certain amount of weight loss). However, I do think both AN/BN psychopathology AND the physiological effects of caloric restriction can interfere with thinking clearly (e.g., there’s research on cognitive impairments with hypoglycemia). I also think the obsession with food/weight can sometimes lead to not thinking clearly (i.e., making poor decisions), although I don’t think this is really all that weight/BMI related (I’m thinking the crazy haze one can get into when bingeing/purging non-stop). There is research on cognitive impairments associated with hypoglycemia.

  4. At the risk of repeating what others have already mentioned in their comments, I also experience(d) huge gaps in my memories. Or perhaps it is that they were largely dominated by food, cold, sleep, and the usual anorexia-misery. If that is all we care about during those acute anorexic phases then nothing else is really on the radar and so we don’t remember a lot about anything else. It’s kind of like that we don’t remember every detail of ever day, only the things that were important to us. Just a thought.
    I know that there were some classes that I really struggled with that I largely attribute to my illness – chemistry, computer science – things like that were impossible for me to grasp. As you can imagine, the perfectionist in me was not having any of that failure and so every assignment, test, class period was torture in those subjects.
    One of the primary (and now kind of funny) examples of my lack of picking up on other things is this: I watched that new Pride & Prejudice movie when I came out and I thought Elizabeth Bennet and Mr. Darcy didn’t get together. Preposterous, right?
    Maybe it’s a defense mechanism, or maybe even after “recovery” there are still the remnants of the eating disorder that take up some of that mental space and so our memory is never going to be fantastic.
    All that to say, thanks for looking into this! Keep up your awesome work 🙂

    • “It’s kind of like that we don’t remember every detail of ever day, only the things that were important to us. Just a thought.”

      Yes, I agree with you. We remember the salient parts.

      “maybe even after “recovery” there are still the remnants of the eating disorder that take up some of that mental space and so our memory is never going to be fantastic”

      I don’t know… I wonder. Perhaps for some, but certainly not for all. Depends on so many factors, it is hard to say. I want to say that I think for most people, there probably won’t be scar effects when it comes to memory but who knows, I’m being optimistic. I don’t know the literature well enough to comment.

      I appreciate your comment KN!

    • Oh there definitively is. Your cognitive abilities can be severely impaired, which is what gives us rational thinking.
      I was totally unable to think clearly, make rational decisions, experience rational emotions. I had “brain fog” and did and said things that were totally inappropriate that I would never do or say now. My reactions to things regarding food were ridiculously intense and disproportional and I was angry the majority of the time.

  5. This is really very interesting. I have huge memory gaps in relation to my thinking and feeling while very ill with AN. Only last year I asked my psychiatrist whether amnesia for the ill state is common. The only evidence I have of my thinking and feeling is from my diaries; and when I read these diaries I am really surprised as to my mindset at the time.

    However, I also find that when I am depressed, I can never remember feeling well – and so cannot imagine ever being well. But when I come out of the depression I struggle to describe it.

    I do not know the mechanism, but I really feel like two different people when I compare a non depressed me to the depressed me. Given that my AN has always been driven by anxiety and depression, I wonder whether depression plays a role in the memory loss that can accompany AN in others too?

    • Hmm, that’s a very interesting point. I think this part: “I also find that when I am depressed, I can never remember feeling well – and so cannot imagine ever being well. But when I come out of the depression I struggle to describe it” is reminiscent of pretty much anytime we are sick or feel unwell. I certainly know it is not just true for AN/BN for me, but also when I have a cold or the flu, I forget what being well was like, and vice versa.

      Also, what did your doctor say? I’m really curious!

  6. I was told that a lack of vitamin B in your diet can stop your brain from forming new memory’s, and if left to long can cause permeant damage? so in treatment I was given vitamin B injections for the first week of re-feeding

    • Yes, I forgot about that – it’s similar to Wernicke-Korsakoff syndrome, caused by lack of Vitamin B1, often found in alcoholism.

    • That’s a good point. Thiamine is definitely important in a lot of cellular processes. But I am not sure, however, about whether a deficiency enough to cause problems with memory is something that would be easily reversible? Memory loss in Wernicke-Korsakoff syndrome is not reversible, as far as I know.

      • I don’t think the memory gaps would have been from Wernicke-Korsakoff, as you say the memory loss seems reversible.
        Every time I’ve been admitted to hospital, the nurses have explained to me that they are giving me thiamine injections to prevent ‘brain damage similar to that in alcoholics’ so I guess it’s possible! The ED unit I’ve been to gives all AN patients 3 days of thiamine injections followed by thiamine tablets daily from admission.

  7. I had anorexia for several years. I experienced significant memory problems during the disorder that were not present before the disorder. Unfortunately, although I am weight restored & behavior free, I still have significant memory problems. I essentially have had to grieve the loss of memories and grieve my ability to store and recall as much information as was possible prior to the anorexia. It is a great loss, but I am alive.

    • Hi Ashley,

      Thank you for your comment. I am really sorry to hear about the memory loss you’ve experienced and the problems you continue to experience. There’s no doubt it is a great loss. That said, I’m really happy that you used the past tense to refer to anorexia — meaning that you are in recovery/recovered/in remission (whichever you prefer, I guess). That is amazing!!

      Again, thanks for your comment.


  8. Russell and Herzog’s work on this topic would suggest there are indeed hippocampus impacts. Also, doesn’t Walter Kaye cover this off too?

    Here is a podcast link via my references section:

    The de-myelination of nerves throughout the CNS impacts the speed and accuracy of electrical signals in all sorts of ways that can be experienced as anything from motor to cognitive impairments. The way Janice Russell describes the de-myelination of nerves for those with AN is that it is a process of throwing the antique furniture on the fire to keep the house warm. The body catabolizes the fatty sheath on the nerve to try to make up for the energy deficits of restriction of energy intake. Such damage will not be easily identifiable through all the different brain scan technologies used today as they predominantly look at relative blood flow to different brain regions.

    And then there’s:

    Hippocampal volume reduction for AN appears to have contradictory evidence. There is the data you mention but also:

    (for general information regarding the immediate reference above, gray matter is correlated with cognitive function)

    This one was particularly interesting because they were looking at neuronal network abnormalities in those with AN (using relative blood-flow analysis). There is definite hyperperfusion in the amygdala-hippocampus complex for those with AN. That means there is increased blood flow relative to the tissue’s need and hippocampal hyperperfusion is a marker we see with Alzheimer’s. That does *not* mean patients with AN have Alzheimer’s! It is rather better to interpret this data that the memory/retention areas of the brain are under duress for those with AN.

    Good news appears to be there is consensus that normalization of morphological changes to the brain associated with self-imposed restriction of food intake reverses with remission of the eating disorder:

    I find the synchronicity of our blogging weird. I am currently working (much more slowly than planned) on a blog post related to the physical damage associated with eating disorders and their resolution (or not) when a patient reaches remission.

    Cheers, G.

    • But do any of those studies correlate the morphological changes with learning and memory?

      I would also want to see how these findings compare to individuals on a CR diet.


        “Hypoperfusion was demonstrated in the anterior temporal lobe and /or caudate nuclei in 8 of 11 patients. No hypoperfusion was identified in the control group. The patient group demonstrated consistent deficits in memory tasks associated with temporal lobe function.”

        “Right dorsal ACC volume was significantly reduced in active AN patients versus controls and was correlated with lower performance IQ. ”

        “Reduced right dorsal ACC volume during active AN relates to deficits in perceptual organization and conceptual reasoning.”

        Of course we’re always looking at really small data sets with AN.

        As for CR and cognitive function, findings were inconclusive in this one:

        “This randomized controlled trial suggests that calorie restriction/dieting was not associated with a consistent pattern of cognitive impairment. These conclusions must be interpreted in the context of study limitations, namely small sample size and limited statistical power. Previous reports of cognitive impairment might reflect sampling biases or information processing biases.”

        I particularly like the following synopsis of all the hype surrounding the animal studies of CR benefits to longevity and brain function:

        “To date, the CRL field has ignored other variables that are crucial to the human case and known to be disrupted by chronic hunger, including sociability, curiosity and emotionality. Promotion of CRL for people is irresponsible in the absence of more reassuring data on the full range of expected outcomes. “

        • Right, I’m not promoting CR, at all. I just think it is an interesting control in answering this question.

        • Sorry, just getting to *actually* reply now since I didn’t have time then, just wanted to make a point that I do not mean to promote CR. (I actually find longevity research quite boring, there’s lots of it in the C. elegans field.)

          I cited the CR study you link to in the actual post, by the way :-).

          Eh, I don’t know why I remain skeptical of this literature. The hypo/hyperfusion stuff, fine. I can see that.

          But changes in grey matter? I don’t know how much of it I’m buying. I would hypothesize that reduction in size and then subsequent restoration of it would mean simply cell shrinkage, as opposed to apoptosis (unless we are talking about hippocampus, where neurogenesis actually occurs, but I don’t know what % of the entire hippocampus newborn cells make-up, at any given point).

          I wonder, also, how the studies you link to relate to the psychology-based theories in terms of “cognitive space.” It would be neat to combine the psych studies with AN patients, a dieting but non-ED group, and healthy controls (and perhaps CR, but imagine trying to recruit for that study!), and look at the psych tests and imaging data, and try to correlate it.

          It is unclear to me (and most likely because I’m not well-read on this) how much of the deficits in blood perfusion and/or structure/volume are due to caloric restriction and how much of them are due to AN-specific mechanisms and/or focus on dieting/restricting?

          Basically, I wonder if someone who loses that much weight but is *not* obsessed with restricting/weight loss, etc (and is otherwise healthy) show the same deficits. What correlates and what doesn’t.

          What a disorganized comment on my part — sorry Gwyn.

          • Not disorganized from my POV, Tetyana.
            I just had to say – your comment made me think about people who are greatly restrictive and who lose large amounts of weight or keep themselves chronically underweight or at least chronically undernourished. My question is – whether they have a diagnosed ED or not – ARE there any people engaging in those behaviors who AREN’T obsessive over food or their weight? Even if they didn’t start out that way, is it possible to stay non-obsessive? Is it possible to live for a
            long term period of time chronically in a state of being so malnourished and restrictive without the biological and psychological effects of the poor nutrition leading to obsessiveness? And at what point do they ‘cross the line’ from dieting or lifestyle type behavior to having an ED or ED behaviors?
            Sorry just thinking ‘aloud’ here 🙂

          • That’s a great question! I have no idea. Probably none/very few? I suppose then it becomes a question of perhaps the content of their obsessions? I have no idea, honestly. I think the Minnesota Starvation Study is useful to think about in this case, but, ultimately, I don’t know.

          • Not disorganized. Of course you cited the same study and by the time I posted it in my comment I had completely erased from memory that I had already scanned it mere minutes ago in your citations. Ugh!

            I didn’t think you were promoting CR at all and I understand you are referring to it in terms of trying to create some kind of distinction between restriction that is anchored in eating disorder and restriction that is not, as a way to determine whether negative cognitive impacts differ or not and whether it would all correlate in some way or not to morphological as well as blood flow changes.

            It could go either way really couldn’t it? Maybe the process is mechanical (no AN or CR differences in cognitive deficits and commensurate physical changes to the brain) or it might be further kindled through environmentally salient ways (brain’s a social organ so this is definitely in the running).

            We know that intoxication is both physical and subjective. There are studies that show people get more “high” smoking weed in certain social circumstances when compared to more spiritual or medicinal settings (sorry, can’t be bothered to even look those studies up…maybe I’ll come back here to post them tomorrow).

            But I suppose it’s also possible that someone undergoing a diet or CR (no ED) might be the one to experience more socially kindled negative cognitive impacts compared to the AN group as well.

            Tough studies to do, unless you decide to create a reality show on all of this – then it’s only going to require those waivers and none of that pesky ethical review stuff!

            Still, really interesting conundrums.

  9. Really interesting post, & interesting points in the comments as well. This will be very un-science-y; I’m a blundering dilettante layman there, so bear with me.

    Trauma was my first thought also. I have a friend with a history of trauma as a young child she (mostly) “blocked out” who also blocked out much of being in treatment. She now theorizes that this is because the trauma was threatening to surface in the absence of being allowed to use behaviors, so she had the smarts to shut those period out altogether, lest the brain pierce the placid surface of recalling what’d happened to her from a different angle via those memories later. In her case, you couldn’t blame her “gaps” on calorie restriction, as she was being refed. I wonder, though, both for patients who have a hx of trauma and those who do not, whether the ED is alluring in part because it allows people to block out things–eg that the memory gaps are (albeit on an unconscious level) part of the motivation to continue restricting rather than the result of restriction.

    I myself wonder quite frequently about changes in cognitive functioning, particularly with long-term eating disorders (and how they might persist or improve post-recovery). What’s research on this like (if there is any) & what’re your thoughts? Are there any clear patterns? I wouldn’t say I have a lot of gaps in my memory of events–there are times, certainly, when I was stupid due to restriction or holidays where all I can recall is the damn chocolate bark that was (and wasn’t) eaten, which correlate nicely with the too-much-attention-to-food-jamming-the-circuits theory you highlight above. In my case, though, my brain does seem to have changed over the years: I am less able to recall words, particularly proper nouns; I have a very hard time organizing my thoughts (and my life). But then again, I’ve never, ever been good at remembering people’s names. I’m just much worse now. So if there’s no clear pattern in the research, is it possible that starvation essentially weakens areas of the brain that were less “strong” on an individual level, rather than creating the same blanket effects on everyone, and that the effects could thus vary person to person? I know, however, that with aging, verbal recall is the first thing to go, so perhaps that’s a bad example- still, along that line, do EDs somehow speed up the brain’s degeneration due to aging (even if CRers say it delays it), or stop it in an earlier state (after all, emotional development often seems to pause with EDs)? And, if these issues persist, how do they differ amongst different types of EDs (and all the intertwined sides o’ crazy that come along with EDs, eg OCD, other addictions, etc)? I would say my disorganization seems to match the chaos of bulimia (which I developed after six-ish years of straight Type 1 anorexia; it’s been another seven years of Type 2 fun) coupled with calorie restriction’s deleterious effects on intelligence et al. But that’s anecdote, not science.

    I don’t know what would & wouldn’t improve with recovery, but I know, flat-out, that this junk makes me stupid. I’ve always found anecdotally, both in myself and others, that all that bunk about anorexia making one clear and sharp was teenage pro-ana hyperbolic horseshit. I remember it doing so briefly, at some point, years and years and yeeeeeears ago…but that was probably adrenalin and newness, & there was a steep bell curve there, and I’ve been on the downward slope for a whiiiiile now. We’ve all met the adult anorexics in treatment whose elevator simply… doesn’t go all the way to the top anymore. I’m just not sure where mine stopped, or if it can restart (I do have to include the caveat that, while much improved, my current nutrition is far from ideal. Still, on the whole, the longer I’ve done this, the stupider I’ve gotten, and that makes me think that something is surely happening in my brain on a cellular level.)
    If there are changes, how much is the result of starvation creating structural changes in the brain and how much is of doing (and believing) really fucked-up, irrational things and said things essentially marching out silly-string neural pathways to Nowheresville? The brain is enormously plastic, as we know. EG in bulimia, where there is often adequate caloric intake overall, do problematic patterns create themselves in the long-term, and how might they differ from the ones in AN?
    For those pesky sick-for-six-months anorexic adolescents who tend to be the sole subjects of studies, I don’t know that medical prodding could find long-term effects later… so the literature here might be crap-tastic. I’ve never found much of use, but I also peruse journals a lot less (because stupid now, obviously.)

  10. I definitely have times during the worst peaks of my ED over the last ten years that Ive had it that are completely “blocked out.” I have always just assumed that I blocked it out because of how dark those times were for me. The only way I know how bad it is is by reading old food journals and diaries where I talk about things…and it is shocking to me now, in my recovery, to realize how bad it really was, because I remembery only a little of it, and I think that also contributed to me being in denial of my illness for so long, because I never acknowledged truly how it had affected my life, and then that also contributed to me having the disorder for so long.

  11. Have you looked into autobiographical memory loss specifically? I think I read a study once that found that people with anorexia (and depression) exhibited very specific forms of memory impairment whereby they recalled more general/semantic memories and had trouble with details as well as the emotional valence. This was only found in personally relevant memories, so a task such as word recall might not pick up on it.

  12. I have experienced memory loss during my most physically (and mentally) sick. The memory gaps are random and not associated with food. For example, I cannot remember a friend coming to visit me at university. She tells me about when she came over to my flat in my first year, but I have no recollection of her ever being at that flat.
    I also experienced memory loss during another very sick period when I was a young teenager.

    • I’d think this supports the hypothesis that the memory gaps are due to a hyperfocus on ED-related things (or well, anything, really that’s more salient)? What do you think?

      • It could be, although what about the brain just being biologically affected due to malnourishment and starvation itself?

        • I think that’s probably possible, I don’t know (as in, I just don’t know enough), but I personally think that’s a less likely explanation than one about salience of the events/content.

          • Maybe. In one of my memory blanks (forgetting an entire overnight visit of a friend to my flat in my first year of university), my only vague recollection of it is eating dinner, and going to Starbucks (both food associated) so in that regard it supports your opinion.

          • Heh, well, it is not my opinion per se, but it is what I gathered from reading the literature for the post.

            I have similar problems. I can’t really differentiate if certain events occurred one winter or the next year’s winter, but I have very specific food-related memories.

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