What’s up with the GAPS diet? 

GAPS – which stands for Gut and Psychology Syndrome – is the invention of Natasha Campbell-McBride – a nutritional therapist based in Cambridge, UK. Her book first came out in 2004 and this is a photo of my copy of the revised version, published in 2011.

I don’t normally write these types of debunking posts but at the time of writing a number of high profile celebrities seem to be backing its use, so I wanted to add my professional critique of GAPS to the information out there about it!

So what is GAPS, what does it involve and how does it rate nutritionally?

It’s difficult to write briefly about GAPS as it is quite a complicated ‘regimen’. The book is wordy and doesn’t really set out any of the steps in a way that is easy to unpick – even for a dietitian.

The headline is that I strongly recommended against trying it. It is not based on good theory or evidence and puts vulnerable people at risk of nutrient deficiencies and overloads. I’m not usually someone who is alarmist but I worry that real harm can be done by following this diet and that in vulnerable people – particularly young children or those with eating disorders it could prove fatal. 

If you are reading this as someone who is already trying this please don’t panic but I’d advise to get medical and dietetic help to ensure your diet is safe and adequate.

So if you want to read on to find out more about what GAPS is – here goes:

Who is it aimed at?

The author proposes that digestive problems are underlying a number of disorders in children and adults (list taken from p7 of her book):

  • asthma
  • eczema
  • allergies
  • dyspraxia
  • dyslexia
  • behavioural problems
  • attention deficit disorder with or without hyperactivity (ADD/ADHD)
  • autism
  • schizophrenia
  • depression
  • eating disorders
  • manic depression
  • bipolar disorder
  • obsessive compulsive disorder

There is no evidence that ‘Gut and Psychology Syndrome’ exists and is not a recognised diagnosis or condition.  In the frequently asked questions section of the GAPS website there are also suggestions of many other disorders that might be helped by the GAPS diet: http://www.gaps.me/preview/?page_id=32. 

Is there any evidence that these disorders are gut-based?

The first 88 pages of the book argue that there is – this seems to be more conjecture than fact – but is written very convincingly. I might try to go into more detail about this in a future post. Many of the claims are debunked here.

What does treatment of GAPS involve?

According to the book the treatment for GAPS is:

  1. Diet
  2. Supplementation
  3. Detoxification and lifestyle changes

The diet is implemented in 3 parts:

  1. Introduction Diet
  2. The Full GAPS Diet
  3. Coming off the GAPS Diet

Stage 1: GAPS Introduction Diet

The Introduction Diet is optional but highly recommended by the author – particularly for anyone with gut problems (see below from p143)

The Introduction Diet has 6 stages which the author says takes a few weeks up to a year to move through:

  1. Homemade meat or fish stock and homemade vegetable soups (from a list of allowed vegetables) alongside water, ginger/mint/camomile tea to drink and probiotics and ‘probiotic foods’ such as sauerkraut, yogurt and kefir.
  2. Introduce raw organic egg yolks, stews based on meat and vegetables, fermented fish, homemade ghee
  3. Introduce avocado, pancakes (made from nut butter, eggs and squash), sauerkraut and fermented vegetables
  4. Add grilled/roasted meats, olive oil, juices, and bread made from nut flour
  5. Add cooked apple, lettuce, carrot, tomato, onion, cabbage
  6. Add raw apple, some other allowed fruits, and allowed homemade baked sweet goods

So what is my take on the Introduction Diet? 

This is basically what would be described by dietitians as a few foods exclusion and reintroduction diet. Few foods diets are used very successfully by allergy and gastroenterology dietitians to uncover food reactions when trial exclusions of other foods helped.

Important differences between the GAPS Introduction Diet and a conventional few foods diet are:

  1. The selection of foods for the exclusion phase (1) aren’t what would normally be chosen and the claims that the chosen foods ‘heal and seal’ the gut are not evidence based.
  2. The range of foods in (1) leave you with a nutritionally inadequate diet. I would always have concerns about using a few foods in anyone who was already nutritionally compromised and would limit the time on the very restrictive phase to a couple of weeks at maximum.  The author of GAPS states phase 1 could take up to a year!!When I analysed the nutritional adequacy of the introductory stage I found it to be below the recommended nutrient intake of vitamins, minerals, protein and calories and would put anyone following it at risk of malnutrition. Bone broth is not particularly nutritious.  Adding in some extra meat to the broth and consuming yogurt a few times a day alongside the broths make the stage more adequate in many vitamins and minerals and higher in protein but it still remains low calorie and relies on the person following the diet consuming at least a litre and a half of soup and broth a day. It is not clear in the supplementation section whether supplements are recommended alongside this phase – in some places this seems to be recommended against – e.g. on the website here it says:
  3. Profuse watery diarrhoea can be extremely unpleasant, a symptom of serious gut problems which need medical investigation and could put children at risk of dehydration.  It’s really worrying to see the advice pictured below on p148 under part 1 of the introductory diet. There doesn’t seem to be anything in the book that says – if you get ill – stop/consult with a doctor. Having heard the author speak at a Western A Price meeting in 2011 she seems to be very dismissive of conventional medical and the NHS.

Stage 2: The Full GAPS Diet

The Full GAPS Diet is recommended to be followed for 2 years. The foods avoided are summarised below.

The selection of foods avoided seem unnecessary and rather random. Justification for foods that need to be avoided seem to be more on the author’s suspicion rather than any science-based criteria.

Analysing the nutrient content of this stage of the diet is tricky as everyone would eat different amounts and variations of the diet each day but mocking up a ‘best-case scenario’ 3 days diet and analysing it showed it to be low in carbohydrates, relatively low in calories but if a variety of foods are eaten, it is possible to meet requirements for other nutrients.  There is a risk of high intakes of vitamin A as liver and cod liver oil are recommended regularly. The scientific basis for this ongoing exclusion is not sound. Unnecessary exclusion diets are not recommended.

Stage 3: coming off the GAPS diet
The author recommends to reintroduce foods after at least 6 months symptom free – but with the below caveat.  It is not clear which foods will remain not-allowed.

Failure to Thrive

The book has a section on p228 that covers ‘failure to thrive’ (an outdated term – now referred to as faltering growth) and recommends:

  • On commencing weaning to avoid giving grains but instead to give bone broth / meat stock and ‘probiotic food’
  • and then to follow the advice in new baby section – which is outdated

Eating Disorders

Worryingly the book has a chapter on eating disorders. I’m not going to go into detail about the chapter as I don’t want to repeat the advice – I think it is incredibly irresponsible and dangerous to be covering eating disorders – the advice is dangerous and concludes as below.


From page 242 onwards the author covers supplementation (see photo below).  I won’t go into this in any detail – like the rest of the book it is quite dense text and not particularly easy to pick out key points.  The supplementation on the supporting website: http://www.gaps.me/preview/?page_id=31 refers back to the book

What else of note? 

There’s a section on constipation – recommending home enemas, a section on pregnancy – recommending regular consumption of liver (which is strongly recommended against in pregnancy due to the risk of damage to the unborn child via vitamin A overload), a section on introducing solids to babies – which is a lot of misinformation, including giving raw egg and delaying introduction of wheat.

Does it ‘work’?

Of course – making dramatic changes to your diet may make you feel great (it may make you feel rubbish too!). If I didn’t believe that dietary changes can have great results I wouldn’t be a dietitian.

There are a number of ways that a dietary regimen like GAPS may see significant changes in someone’s health or behaviour:

  1. If you have a previously uncovered food hypersensitivity then avoiding that food will remove troubling symptoms.
  2. It is pretty undisputed that our gut flora have a lot to do with our health and dietary changes and probiotics can change our flora – which can change many aspects of our health.  Note that fermented foods (sauerkraut, kefir, etc) aren’t proven to have a probiotic effect though. 
  3. If you have deficiencies and change your diet and take supplements to correct this may remove troubling symptoms
  4. Just the process of making a dramatic behaviour change like eating very differently can have a placebo effect – which can be marked!

That doesn’t mean that this diet is necessary or anything more than a confused collection of exclusions.

I’ve supported a number of people who have tried GAPS – mostly parents who have tried it on children with autism spectrum condition – most didn’t get past the first week or two – and I now try to talk parents out of it – so they often stop once they have spoken to me.  I have had to consider referrals for safeguarding when children’s growth have faltered on this and other diets, or when I have been concerned about risks of deficiencies.  I have never heard of a child death on this diet (although unfortunately I have on other restrictive diets) but have heard of a child who ended up on intensive care a couple of years ago – a couple of weeks into this diet.  An extra issue with it being recommended for children with autism and other special educational needs and disabilities is that these are often children who don’t accept new foods well and are often nutritionally vulnerable and so are at even higher risk of an inadequate intake on GAPS.

It is interesting that in this article a US paediatric gastroenterologist who seems open to this diet says he has not seen great results on it.

So why do I think this diet is dangerous?

  1. The author has a medical qualification (MMedSci – Russia) and nutrition (MMedSci Nutrition – UK) qualification but is not registered with the bodies regulating doctors or nutritionists (the GMC or AfN) in the UK.  Many people who ask me about the diet feel that with these qualifications ‘she must know what she’s talking about’.  However, the author uses pseudo-science and implies her opinions are scientific fact throughout her book –  and uses various techniques that are common in sales of alternative therapies.  Following the advice of an unregistered person is never recommended. Previous qualifications are not the same as current registration and regulation – which are safeguards that a person is safe to practice.
  2. There is no evidence-base for the ‘diagnosis’ of GAPS or the diet – except for various testimonials.  It is very restrictive and not based on any sort of scientific or common-sense criteria for foods excluded.
  3. There is a risk of people becoming malnourished on this diet – particularly the introductory phase – and a risk of vitamin A overload in the full diet phase.
  4. The author dismisses worrying gut symptoms  – with no warnings of when to get medical help.
  5. The author advises not to take supplements that have been prescribed.
  6. The author gives advice on diet in pregnancy and infancy that contradicts government food safety guidance – liver intake in pregnancy is not recommended.  Raw egg in infants is not recommended.
  7. The author gives advice in the frequently asked questions on her website around weight loss, gut symptoms, and medical disorders.  Much of this is not in line with standard medical advice.
  8. The book is lacking in clarity as to what exactly should be eaten at each stage and particularly on ensuring the diet is nutritionally adequate.
  9. The author has opinions on vaccinations that are not in line with public health advice.  (from http://www.gaps.me/preview/?page_id=34)
  10. The author gives dangerous advice on eating disorders and proposes they can be treated with GAPS.


Please steer clear of GAPS – and anyone who advocates it.

I am generally open-minded, patient-centred and willing to work with patients who wish to try alternative / complementary therapies including different dietary approaches.  Diet can play a huge role in health and overcoming illness.  However it is important not to follow approaches that carry risks of nutritional deficiencies and that are accompanied by dangerous philosophies and dangerous medical advice.

If you have concerns about your gut health please contact your GP.  If you have concerns about your diet or wish to try exclusions or additions to your diet then you can request a referral to a registered dietitian via your GP or sometimes contact your local NHS department directly.  To find a private dietitian search at http://www.freelancedietitians.org/


  • Campbell-McBride Natasha (2010) Gut and Psychology Syndrome Pub: Halstan & Co Ltd, Amersham, Bucks ISBN 0-9548520-2-8

Other posts critical about GAPS

Some sources of evidence-based nutrition info include: