Anorexia & Gut Health… What Does the Research Say?

Having attended a conference at the Royal Society of Medicine looking at the role of diet in mental health last week, I have had a lot of requests to talk more about gut health and anorexia. I always think it is beneficial to team up with other professionals in the field so I have invited the wonderful Bari the Dietitian (@barithedietitian) – (who also happens to be my best friend!) to help me document what we know about this area of research. Bari and I met on our postgraduate MSc programme and she happened to do her final research project looking at this exact area! We hope you enjoy the read!

What is Anorexia?

Often misunderstood as a disorder of vanity, Anorexia Nervosa is the mental health disorder with the highest mortality rate of all psychiatric disorders. It is characterized by extremely low body weight, insufficient food intake and intense fear of weight gain… Anorexia does not discriminate based on age, gender, race, socioeconomic status, etc., but the demographic with the highest prevalence rate in females of 0.4%. As the exact cause remains unknown, treatment is a complex obstacle.

Additionally, what makes treating this disorder so difficult, is the fact that different individuals respond differently to various forms of treatment.

Consequences of anorexia include a range of both physical and psychological side effects. Some of these include malnourishment due to extreme weight loss, feeling tired, faint or dizzy, osteoporosis, digestive issues, and weakened immune system.

What is Gut Health and Why Is It Important?

Gut health seems to be a term that is thrown around a lot these days, as it has become “on-trend” in the media, and for good reason! Our guts are home to billions of bacteria, viruses, and fungi, which have a combined weight of approximately 1kg – fundamentally the same weight as the human brain. The gut microbiome (all the microorganisms and their genetic material) has a strong impact on digestion, immunity, metabolism, as well as mental and brain functions.

A “healthy” gut is described as having a wide range of diversity! On the other hand, a sub-par gut is described as the loss of beneficial microorganisms, the expansion of harmful microorganism, and/or the loss of overall microbial diversity.

The microbes in your gut also communicate with your brain via the “gut-brain-axis”. This means the bacteria that inhabit your gut can talk to, and influence your brain regarding mood, stress, and anxiety.

Interestingly, new research is now suggesting that our gut microbiome may be affected and ‘altered’ by various different factors. We know that antibiotics can have a negative effect on gut health, and it is advised that probiotics are taken alongside them, particularly if taken for a prolonged period of time. A body of research also tells us that our gut loves fibre (found in fruit, veg, and whole grains). In fact, it is recommended that we eat around 30g of fibre a day and the average intake in the UK is only around 18g.

What Does the Research Tell Us About Gut Health In Individuals Who Suffer From Anorexia?

Our gut bacteria are greatly influenced by the foods we eat. Therefore, the lack of food and associated malnutrition can alter the gut microbiome and result in sub-optimal conditions. Here are some negative side effects of Anorexia Nervosa (AN) in relation to the gut:

  1. Decreased intestinal wall thickness, which leads to increased permeability of the gut, can increase the risk of infections and inflammation, and cause GI symptoms, such as bloat, pain, and inevitable “leaky gut”. This also increases the risk of developing an auto-immune disease.
  2. Microbial diversity decreases and the quantity of harmful bacteria increases. For example, those with Anorexia have higher concentrations of M. smithii, which has been shown as an adaptive mechanism in patients with AN to achieve optimal extraction of calories from very low-calorie diets.
  3. Dysbiosis (sub-optimal bacteria profile) also exists in those with depression, OCD, and anxiety, all of which are co-morbidities of Anorexia. Additionally, the low mood experienced by those suffering from Anorexia may be due to the poor nutritional intake. Thus, AN may promote low mood, which then contributes to the progression of the disease, which makes treatment more difficult.
  4. A gut-healthy diet rich in fermented foods and low in processed foods has been shown to reduce symptoms of stress and anxiety.
  5. Recently, however, there has been compelling evidence that the intestinal microbiota may regulate symptoms and maintaining factors of AN, including weight, energy metabolism, immunity, anxiety, and depression. Variations in gut bacteria may be associated with extreme weight loss, thereby perpetuating AN via direct effects on weight and mood.


Why Is This Important?

Good gut health is important for digestion and AN sufferers usually experience a lot of digestive discomforts. What we don’t know yet is the types of anorexia that may have a more detrimental effect on the gut. More research is needed to identify whether or not gut symptoms are worsened by prolonged periods of food restriction and purging, for example. Although AN behaviors and symptoms differ from person to person, the present research strongly indicates that poor gut health is associated with this mental health disorder and when treating this illness, gut health research should be used as a tool for recovery.

So, the big question remains: Is an altered gut microbiota simply an obvious result of long-term reduced food consumption, potential dietary deficiencies, and weight loss? Or, alternatively, does microbial composition have the potential to cause these metabolic outcomes and possibly, to contribute to disordered eating behavior? We need more large-scale follow-up studies to clarify these relationships. However, this may offer novel ways to treat eating disorders, specifically Anorexia!

If you are suffering from disordered eating patterns and digestive issues as a result, please seek help from a qualified professional. Other helpful resources can be found at

To book a Nutrition Consultation with me in clinic, please email me at

When does healthy become unhealthy?

When does healthy become unhealthy?

by Sophie Bertrand BSc, MSc and Dr Alison Colville MbCHb, MRCGP, LFHom (med) 

Having completed an MSc in Nutriton and eating disorders, I am very family with the research surrounding the topics of anorexia, bulimia and binge eating disorder. However, we are now being faced with the rise of a condition named ‘orthorexia’ which describes an individual that will avoid all foods that they consider to be ‘unhealthy’ thus becoming extremely restricitive in regards to their eating habits. Being that this condition is not yet listed in the Diagnostic and Statistical Manual of Mential Disorders (DSM-5) it can be somewhat difficult to diagnose. Being that my ethos is centred around encouraging idividuals to have a healthy relationship with food, I wanted to ask for General Pracitoners perspective and her understanding of orhorexia to help educate individuals who find it difficult to separate the idea of being healthy and having a good relationship with food from only eating ‘healthy foods’. Myself and GP Alison Colville (also known as ‘The Wholehealth Doctor’) have teamed up to hopefully clear up and answer any questions surrounding this topic.

When does healthy become unhealthy?

Is it when we start choosing organic over non-organic? Is it when we turn down dinner with a friend because you know they won’t have dairy free options? Or perhaps it’s when you spend your day planning your meals for the following day? The truth is, it is very hard to tell. Individually, these can be health conscious behaviours to have but when they start to negatively impact your mental state, relationships or day-to-day life then perhaps things have gone too far.

What is Orthorexia Nervosa?

ORTHOREXIA NERVOSA was first described in 1997 by a man called Bratman who found his behaviour around food and health becoming obsessive whilst running a health retreat. [1]

After a year or so of this self-imposed regime, I felt light, clear headed, energetic, strong and self-righteous.  I regarded the wretched, debauched souls about me downing their chocolate chip cookies and fries as mere animals reduced to satisfying gustatory lusts.  But I wasn’t complacent in my virtue.  Feeling an obligation to enlighten my weaker brethren, I continuously lectured friends and family on the evils of refined, processed food and the dangers of pesticides and artificial fertilizers.’

Does this sound familiar?! You can read the rest of his story at

Although not currently recognised as a disease by Psychiatric diagnostic guidelines, Orthorexia is a condition which is becoming increasingly diagnosed. There are differing views as to whether it is a ‘disorder’, a ‘behavioural addiction’ or an ‘extreme dietary habit’[1]. Particularly amongst those with a history of mental illness or in recovery from other eating disorders. Essentially, the condition is characterised by obsessive behaviour surrounding the perfect diet and other healthy actions such as excessive exercising, use of supplements, and extending into ritualistic selfcare practices.

As I wrote this article, I realised that in my GP practice I have never diagnosed this condition, or in fact, come across it all. Does that mean perhaps it doesn’t exist? Well, the evidence suggests the otherwise, so clearly, we are not aware of its existence, both the individual and the healthcare professionals. When we are eating ‘healthily’ and striving to improve our health or fitness we think we’re far from having a problem and so this is not something that we would seek help about. Interestingly, Orthorexia is a condition where the individual talks freely about their food habits, quite the opposite to those suffering with Anorexia Nervosa.

How do I know if I have it?

The ORTO-15 is a questionnaire which has been developed to identify those who may have Orthorexia[6]. It clearly has it’s limitations, namely in it’s lack of standardisation and also cultural variations. However, it is a useful tool to make a general assessment of someone’s attitude towards their food and health. As a practitioner of lifestyle medicine and promoter of health, some of the questions I believe to be health conscious behaviour rather than specifically destructive e.g. ‘Are you willing to spend more money to have healthier food’ but see how you score….

  Always Often Sometimes Never
When eating, do you pay attention to the calories in the food?
When you go in a food shop do you feel confused?
In the last 3 months, did the thought of food worry you?
Are your eating choices conditioned by your worry about your health status?
Is the taste of food more important than the quality when you evaluate food?
Are you willing to spend more money to have healthier food?
Does the thought of food worry you for more than 3 hours a day?
Do you allow yourself any eating transgressions?
Do you think your mood affects your eating behaviour?
Do you think that the conviction to eat only healthy food increases self-esteem?
Do you think that eating healthy food changes your lifestyle? (frequency of eating out, friends…’?
Do you think that eating healthy food may improve your appearance?
Do you feel guilty when transgressing?
Do you think that on the market there is also unhealthy food?
At present, are you alone when having meals?

L.M. Donini, D. Marsili, M.P. Graziani, et al. Eating Weight Disord. 10: e28-e32, 2005


Scoring grid

Question Responses
Always Often Sometimes Never
2 – 5 – 8 – 9 4 3 2 1
3 – 4 – 6 – 7 – 10 – 11 – 12 – 14 – 15 1 2 3 4
1 – 13 2 4 3 1


The impact of social media

Probably the most shocking research I discovered was a study done by Turner et al[5] who used the ORTO-15 questionnaire on 680 social media ‘health food’ account followers and found that a staggering 49% of them fit the criteria for Orthorexia. A similar study was done on random members of the public and found only 1% to fit the criteria. Interestingly, these figures are only linked to Instagram and not to other social media platforms. A further Austrian study by Kinzyl et al[4] found that up to 55% of the dieticians they examined also exhibit behaviour consistent with Orthorexia.

Anyone on social media promoting food, wellness or any other practice of healthy lifestyle is potentially feeding into this. So, this begs the question… Are we feeding into this? As a doctor my goal is clearly to make people BETTER or restore their health and certainly not to drive an eating disorder. Ultimately, we need to be aware that this condition does exist and promote self-reflection in our eating/health habits to ensure that we don’t slide into more unhealthy habits. It is so important to have balance in all aspects of life and practicing mindfulness, meditation and journaling are fantastic ways to help us see through our actions and become more self-aware.

How to keep a healthy mindset

Try to go easy on yourself from time to time. You don’t have to be perfect, because perfection never ends. If you forget to meditate one day, or you’re invited to eat at a friend’s house, or even if you just need to sleep and have a bath rather than exercise, forgive yourself and move on. The 80:20 rule is a very useful rule to stick to: eat well, exercise, 80% of the time, and allow some flexibility for the other 20% of the time.

What we have to remember is that good food makes us happy, and being incredibly restrictive around food will ultimately leave you feeling unhappy. Food is to be enjoyed, it is fuel, it is energy, and cutting out food groups such as diary, is not going to have any positive impact on your health unless of course you are intolerant to it. Variety is key, and the more colours and varitey of foods you have in your diet, the better your gut health will be thus the healthier you will be. So try not to stick to such a restricted way of eating because the truth is, it is not healthier!

If you feel that your behaviour around food is becoming destructive to your life then please seek help from your GP, even if it’s just to talk things through. Some other supportive resources include:

Co- Written by Sophie Bertrand MSc and The Wholehealth Doctor

Dr Alison Colville MbCHb, MRCGP, LFHom (med)

Public speaker and GP with a specialist interest in lifestyle medicine and wellness


[1]            Orthorexia nervosa and self-attitudinal aspects of body image in female and male university students / Donini et al / Journal of Eating Disorders 20153:2 / January 2015

[2]            The stigma of clean dieting and orthorexia nervosa / Nevin et al / Journal of Eating Disorders20175:37 / July 2017

[3]            The interrelationship between orthorexia nervosa, perfectionism, body image and attachment style / Barnes et al / Eating and weight disorders – studies on anorexia, bulimia and obesity / Vol 22 Issue 1 pp 117-184 / March 2017

[4]            Orthorexia nervosa in dieticians / Kinzyl et al / Psychother Psychosom 2006;75:395–396 / October 2006

[5]            Instagram use is linked to increased symptoms of orthorexia nervosa / Turner et al / Eating and weight disorders – studies on anorexia, bulimia and obesity / Vol 22 Issue 2 pp 227-284 / June 2017

[6]            On orthorexia nervosa: A review of the literature and proposed diagnostic criteria / Bratman et al / Eating Behaviours Vol 21 pp 11-17 / April 2016