Is anorexia due to food intolerance?



  • Until now, anorexia was thought to be psychological
  • New research suggests that anorexia is at least partly a metabolic disorder
  • Our readers say their anorexia was cured when they did the elimination diet that we recommend

A worldwide study published last month suggests that anorexia nervosa is at least partly a metabolic disorder, and not purely psychiatric as previously thought. One hundred researchers studied 16,992 cases of anorexia nervosa and 55,525 controls, from 17 countries across North America, Europe, and Australasia.

Main findings of the study included:

  • the genetic basis of anorexia nervosa overlaps with other psychiatric disorders including obsessive-compulsive disorder (OCD), depression and anxiety
  • genetic factors associated with anorexia nervosa also influence physical activity, which could explain the tendency for people with anorexia nervosa to be highly active

The food intolerance link

From our point of view, obsessive-compulsive disorder (OCD), depression, anxiety and hyperactivity are already well-known symptoms of food intolerance. For years, our readers have been telling us that their eating disorders - including anorexia, bulimia and binge eating, often associated with depression, OCD or ADHD (hyperactivity) - are due to food intolerance, and go away when they avoid the foods to which they have an intolerance. 

There are suggestions that food intolerance itself may be a metabolic disorder (Breakey 2004). For example, people for whom SSRI antidepressants don’t work can do extremely well on diet (Parker & Watkins 2002, and our reader stories). It has been shown that children with food intolerance are slow or null metabolisers of cysteine dioxygenase which is one of the CYP450 enzymes (Breakey 2004), the same enzyme system that cause problems with psychiatric drug intolerance. Similarly, amine intolerance is linked to a missing or low variant MAO gene that leads to low levels of monoamine oxidase (the enzyme that helps to metabolise tyramine) that can lead to headaches and aggression - what we would call amine intolerance. The ability to metabolise propionate preservatives is dependent on the Propionyl CoA carboxylase enzyme associated with PCCA and PCCB genes, which has been shown to be of variable expression. So it seems possible that anorexia could be just one more manifestation of food intolerance.

People in the Food Intolerance Network regularly report managing eating disorders with diet.

Reader reports

I am 23. I led a high achieving, healthy active lifestyle until 6 years ago ... Bulimia progressed to Severe Bulimia, Binge Eating Disorder, Anorexia, hospitalisation ... a week after finishing programs I was back to my old habits ... I found your website ...  started cutting out the 600 number flavour enhancers and the 200 number preservatives ...  instant recovery ... now I'm trying to cut out the rest of the nasties too ... It's been nearly 2 months - I feel so free ...  I rarely have my crazy OCD thoughts filling my head .. - Jayne from story [1116] 

As a young girl ... I was just VERY energetic ... From the age of 16-22 I suffered from Bulimia & Bipolar (formerly known as manic depression) and ... the food intolerances affected me the worst (sinus, IBS, fatigue, migraines) ...  I accidentally picked up one of your books ... I started the elimination diet the next day. Within 3 days the sinus problem completely disappeared ...  A few months after I did a complete turnaround in my diet .... through the strength and clarity that I was starting to experience in my mind and body, I decided to apply for uni ... and I LOVE IT! And it wouldn't have been possible, without your help - from story [1414]

I am 15 ...  I have experienced a range of symptoms ... ODD, OCD, depression and anxiety, IBS symptoms ...  I decided to do the diet, but take a break ... I went to summer camp and ate EVERYTHING ... tons of high salicylate fruits and LOTS of artificial junk (candy, cake, lots of artificial preservatives, etc.) as well as lots of amines, dairy, some wheat and soy (all of which I now know I am sensitive to). Because of this, I developed an eating disorder, extreme anxiety, depression and worsened ADHD and stomach problems. I was under-weight and recommended to an Eating Disorder Clinic ... I was so miserable ... I decided to start this diet up again. ...  As I slowly cut out the foods I was sensitive to ... The eating disorder, depression, anxiety, obsessive thoughts and awful stomach aches and pains went away!!! It was amazing!!!! - 15 year old in the USA, from story [1439] eldest son was diagnosed with PDD, ADHD, anxiety disorder ... as well as bordering on anorexia nervosa ... at the age of 10. Doctors and the drugs they threw at us weren't helping .... We started FS (Failsafe eating)  ... and now only a couple of months later my son looks and acts like a "normal" child... from story [1115]

I can't tell you how happy I am to have found FAILSAFE  ... . It's only day three and I feel like a different person ... If this diet works ... you will have literally saved my life ... Words can't describe how ill and depressed I had become ...  No doctor wanted to help, couldn't help or just didn't believe me .... Update after one month - the depression is the best it's ever been ... Looking back at my childhood ... I had terrible shyness, was afraid of everything ...  fluctuating weight and eating disorders (binges and starving) ... Update after 6 months – I am happy to report ongoing improvements in overall mental, emotional and health conditions ... - Liz  from story [963]

Your book and your website have saved us ...  Our beautiful 8-year-old is back to normal after a year in the wilderness where we wondered if she was depressed, had an eating disorder or a mood disorder ... - from story [723]

Is there a link between food additives or salicylates and anorexia? Our youngest daughter while off diet is seriously disinterested in food. Between the ages 3 - 9 she was in the lower percentiles weight wise. There were also some indications of her being obsessed with low weight and being skinny. We did the diet for her behaviour ... With the diet partially sorted out her relative weight for her ages has gone up ... - ­ Peter from story [114]

"Fobbed off by other health professionals"

Ironically, in 2013 a Medical Journal of Australia article insinuated that low salicylate elimination diet could actually cause eating disorders. 

Here is the answer I liked from award winning dietitian Joy Anderson:

"As a dietitian who uses the RPAH Allergy Unit Elimination Diet in my everyday practice, I can assure you that it does work brilliantly in the majority of cases .... The diet should be supervised by an Accredited Practising Dietitian with experience in food-chemical intolerances and conducted as a test diet, for a limited period of time - usually only 3-4 weeks in duration. Occasionally it may go longer, but the dietitian ensures that nutrients are adequately compensated for. The challenges are then performed in a timely manner and the diet refined to be liberalised as much as possible, while only avoiding the problem foods long term. I have many, many satisfied clients who were fobbed off by other health professionals in the past, because they didn't 'believe' in food-chemical intolerance" - letter from Joy Anderson AM in the June 2013 issue of the Medical Journal of Australia InSight

What doctors should recommend

There are no scientifically proven laboratory tests to diagnose food chemical intolerance. The way to find out exactly which foods and food chemicals are causing the problems is to do a 3 week trial of the RPAH Elimination Diet followed by careful challenges and supervised by an experienced dietitian, as recommended by dietitian Joy Anderson above.

More info

Our list of supportive dietitians in every State and overseas
Intro to food intolerance
How to start failsafe eating 

Factsheet on eating disorders and food intolerance


Genetic study reveals metabolic origins of anorexia, July 15, 2019, Science Daily,

Watson HJ et al, Genome-wide association study identifies eight risk loci and implicates metabo-psychiatric origins for anorexia nervosa.Nat Genet. 2019 Aug;51(8):1207-1214.

Breakey J, Is food intolerance an inborn error of metabolism? Presentation at the Nutrition Society of Australia Conference, 2004.

The enzyme system that cause problems with psychiatric drug intolerance: Parker G1, Watkins T, Treatment-resistant depression: when antidepressant drug intolerance may indicate food intolerance, Aust N Z J Psychiatry. 2002;36(2):263-5.

 Amine intolerance and low levels of monoamine oxidase: Caspi A et al, Role of genotype in the cycle of violence in maltreated children. Science 2002;297(5582):851-4.
and see our Amines factsheet for more references

Propionate intolerance is the same as chemically-induced propionic academia (a metabolic disorder associated with genetic enzyme deficiency): Brusque AM et al, Effect of chemically induced propionic acidemia on neurobehavioral development of rats. Pharmacol Biochem Behav. 1999 Nov;64(3):529-34. and see our Salicylates factsheet for more references

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