What causes an eating disorder? Psychology, biology and genetics

What I’ve realised is that a lot of people have their own ideas about what causes an eating disorder, what is and isn’t eating disordered behaviour and if it is so very different from dieting or other weight loss methods in the end. Also, a lot of other people haven’t ever really thought about it or considered it because it’s never something that has entered their lives in a particularly significant way.

When I started to tell people about my concerns around my eating disordered behaviour I was met with kindness but also a lot ignorance. As I’ve mentioned before, a lot of the behaviours that form an eating disorder are very normalised in our culture and thus are able to be minimised or go unnoticed. I feel that it was not until I started to look the part that my behaviours were taken seriously or I was asked if something was wrong more directly.

Some popular responses as to why people get eating disorders are: that they want to feel a sense of control, they want to look like a model, influencer or celebrity, they feel insecure about their body or maybe they have some sort of trauma. I don’t think any of those are totally untrue but they are all quite over-generalising, simplistic and, in some cases, dismissive ways of looking at something complex. In my view even the diagnostic criteria for a lot of eating disorders perpetuate these ideas in unhelpful ways. It assumes a straight-forward relationship between behaviours, aspirations, desires and motivations.

My own experience is that my eating disorder did begin with a desire to lose weight but where that desire comes from is the thing that is often overlooked. The assumption is that young girls are simply vain and obsessed with their looks and so pursue thinness to this end. I’d firstly argue that when the world is constantly rewarding thinness, positing it as strictly positive, desirable and aspirational I wouldn’t be so judgemental about a desire for this type of appearance. Thinness represents something more than simply ‘looking hot’ – it means being successful, able to attract sexual and romantic partners, getting everything you want in life, achieving something, being disciplined, being better. Of course this is an attractive prospect to a teenage girl (the demographic stereotyped as the one’s who have eating disorders) but it is also an attractive prospect to many others for different reasons. When you’re marginalised it seems to give you access to power and desirability you may have been denied. This, at least, is something you seem to be able to change about yourself.

This is how it felt to me – the deep unhappiness I felt with myself and my body seemed to have an obvious solution: change it. When you experience gender dysphoria this can be an attractive prospect. I think also when you experience racism, sexism, disableism – all of these things that are about your body – it makes sense to feel that you should change your body. So, I think this can certainly be a trigger for an eating disorder but I wouldn’t say that’s all.

Theories about why we carry out eating disordered behaviours when they are so deeply counter-intuitive seem to fall into a few schools of thought: genetic, psychological and biological. I do want to point out that from an evolutionary stand point it obviously makes no fucking sense to restrict our food intake and over-exercise, or use purging behaviours. Many other behaviours associated with mental illness don’t make much sense in this regard either so usually we theorise that there has to be something in our brains that is malfunctioning in some way to make us carry out these behaviours.

From a purely psychological perspective the theory seems to go that we are able to carry these behaviours out due to sub-conscious beliefs and traumas which affect our conscious mind and choices. So, it makes sense to look at our past, our beliefs about ourselves, why we might have low self-esteem and a need for control due to feeling ‘out of control’ in our own lives. These are all what I would consider psychological reasons for the behaviours.

What’s interesting about anorexia and restrictive type eating disorders (which it’s arguable all eating disorder are to some extent) is that, once the behaviours like restricting food have begun, there are a plethora of other kinds of behaviour that seem to happen as a result of the body going into ‘starvation mode’. Of course, your body is going to try to protect itself against any perceived scarcity or lack of food and this will have a significant impact not only on your physical body but also on your mental state. Most people recognise their behaviour changes when they are very hungry – you become irritable, tired, light-headed and maybe even aggressive. The average person would combat this by obtaining food as quickly as possible. But what happens when you don’t do this? What happens when you’re in a constant state of hunger? What does your body do?

Every single thing I’ve ever read about eating disorders will reference the Minnesota Starvation Experiment – if you’ve done any reading at all about it you will have read about this. Basically, back in the old days when we didn’t have Ethical Approval Committees some scientists who wanted to learn about the effects of starvation and how to re-feed prisoners of war who’d been starved decided to do a study on some ‘healthy’ fairly young men by keeping them on rations over a period of 6 months and observing the effects. Suffice to say; ‘semi-starvation’ fucks you up. The men reported low mood, irritability, social withdrawal, isolation, reduced cognitive functioning, low sexual interest, food obsession and in some cases even psychosis.

The reason so much literature quotes this study is because it mimics quite effectively how eating disorder restrictive behaviours impact people’s behaviours and also biological processes. That is to say that some of the behaviours associated with restrictive eating disorders are behaviours that are being produced by being in a state of starvation. Some of the men in the experiment also exhibited ‘binging’ behaviours when they were able to escape the conditions of the study and ate as much food as they could in these times. Many people with restrictive eating disorders ‘binge’ on food with varying regularity – their body seems to take over and they find themselves eating and eating without much enjoyment. I’ve seen compelling arguments that this is what Binge Eating Disorder really is – the body trying to get more food after some form of restriction around it. Perhaps not the more extreme restriction we see in anorexia but restriction nonetheless can cause this behaviour and biological response in the body.

My own experience of this fits all the literature – I was shocked to find this, having been convinced that my behaviour and thoughts were utterly deranged and illogical. When I was restricting I expected to be more tired, perhaps, a little hungry. There is sometimes an idea that people with eating disorders simply don’t experience hunger. This is certainly not the case for me. My experience when restricting was that I was almost constantly hungry and using a variety of tactics to deal with this; incidentally a fair few of which I found on diet and weight loss advice sites. I was constantly on edge, far more irritable, short-tempered, withdrawn. I was constantly planning my food and exercise, completely obsessed with food, scrolling through Instagram looking at all the vegan food pages, recipes and tips. I would go into supermarkets and food stores and stare at the food there but never buy it. Just imagine I was.

But why would you carry all this on if you didn’t have to? Is the desire for thinness really strong enough to push through this torture? I think this is why people think being thin is about ‘discipline’ or that people with restrictive eating disorders must be very disciplined people. It seems like being able to override our biological needs is seen as something virtuous. Just, maybe people with eating disorders have taken it all a little bit too far.

I recently took part in a UK wide genetic study on eating disorders through the Eating Disorders Genetic Initiative (EDGI). I filled out a questionnaire and then was sent a kit to provide a genetic sample aka spit in a tube. Genetic testing on a wide scale has been happening more and more in recent years to try and provide us with some data on people with similar conditions and what sort of things might be present in their genetics that could indicate why they were vulnerable to the disease in the first place, what might make effect treatment and whether there are environmental or epigenetic factors at play in certain populations. This has been done for things like breast cancer, for example, and had some promising results.

There has already been a wide scale genetic study on eating disorders in Northern Europe which has identified some possible genetic similarities and factors in people with eating disorders. This research, by Dr Cynthia Bulik and her team, seems to support the argument that there are genetic factors influencing the development of anorexia and they argue that it is a ‘metabo-psychiatric’ disorder. This basically means that people who develop anorexia may have genetic differences in the way that their metabolism functions which are equally important as the psychological components of the disorder. There is also genetic overlap with other mental illnesses like OCD, depression, anxiety and schizophrenia which, I think, is to be expected.

What appeals to me about genetic explanations for eating disorders is the seeming disparity in how things like dieting seem to affect people. Why is it that my first ever attempt to actually diet led me into a full blown eating disorder so dramatically? Is it just that I’m some sort of hyper-perfectionist, ‘Type A’ personality (whatever the fuck that means)?

In Tabitha Farrar’s books and blog she is a strong proponent for the ‘migration theory’ of eating disorders. This is the theory that people who develop eating disorders do so due to an epigenetic adaptation that appears and is activated in certain people when they go into starvation mode. The idea is that in ancient times certain human’s response to a famine would have been to migrate to an area where food was more plentiful. In order to do this effectively they would have needed a large compulsion to move and also not to stop at the first sign of food – they’d need to wait until they got to the mother-load. Thus, their brain would tell them that they did not need to eat much at all but rather needed to keep moving as far as possible. When this response was activated in their brain they’d be able to effectively migrate to where a better food source was. Upon arrival, they’d feast and rejoice and be able to switch back to ‘normal’ after adequate feasting and restoration had occurred.

So, the theory would be that in modern times certain people’s response to perceived starvation would be for their brain to activate this migratory response. This explains why anorexic people feel a compulsion to move a lot (exercise) and eat little (restrict). The problem being that the ‘feast’ moment doesn’t come because there is no obvious time when it should happen. There is not actually a famine happening; the famine is artificial. The brain was, theoretically, only meant to invoke this migratory behaviour for a relatively short period of time; days, weeks, maybe a few months at the most. When no feasting takes places to ‘shut off’ the response it continues and becomes more and more ingrained and thus more difficult to get out of, as we have then created neuro-pathways which incentivise these behaviours and responses to food and movement. It becomes more and more difficult to simply stop these behaviours as time goes on.

Of course, almost all of this theory is pure speculation and there is no way to ‘prove’ that this is, in fact, the case. It is a well-researched bit of theory with evidence pulled from a variety of historical, psychological, genetic and biological studies of eating disorders and seems very compelling as an explanation but we will never really know if it’s the case.

This does fit in somewhat with some of the genetic testing and could explain, for example, what may have led to people having these genetic predispositions. The idea that my diet may have triggered some sort of genetic, biological response in my brain and this is why I went on to develop my eating disorder does feel compelling to me in many ways.

Farrar and others sometimes use this to entirely reject any sort of psychological element in eating disorders and the need for psychological intervention in eating disorder recovery. I think that, although the psychological factors are massively over-emphasised in most treatment programs I’m aware of, they are not without value – particularly in uncovering what led someone to be unhappy enough to begin their restriction or purging behaviours in the first place. Yet I have to agree that what feels like the most important intervention is finding a way to start eating again and getting out of the state of starvation. I think this can include psychological coping mechanisms to deal with the fight-flight response that is invoked at the idea of eating and stopping movement.

The causes of eating disorders and why they may develop is an important topic in the sense that it affects how they are treated but also public perception and personal insight by the sufferer. Learning what I have, questioning myself and explaining what I’ve learnt to others has been really key in my recovery so far. I have a lot of issues with being told what I ought to be doing (maybe it’s my Type A, controlling personality) so figuring it out for myself and trying to implement it has felt empowering to me. It hasn’t been easy but I’m fortunate to have plenty of support from others. I think anyone who recovers or tries to recover is incredibly strong because we are constantly fighting our own very primal responses to things.

Being genetically predisposed to something doesn’t mean it’s a permanent state of things and there are many success stories out there of people who were able to recover. I wouldn’t want any of this to come across as deterministic so to be clear: I very much believe that, with the right support, one can recover from an eating disorder and being genetically predisposed is not that same as being genetically predetermined. The human brain has an amazing amount of plasticity and we are able to survive, change and adapt. It isn’t easy and I’ll be writing more about the barriers and fuckery of the NHS and other bureaucracy one encounters soon but, in my own hodge podge way, I’m making it.

Note: I haven’t done as much research into genetics of bulimia and other types of eating disorders but I am interested if others have anything to point to or say on this, too!

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