The GAPS diet: two years of broth and big promises, zero trials.
The GAPS diet says it can treat autism, ADHD, depression and a long list of other conditions by healing the gut. Nobody has tested that in a single published trial. Here's what the diet asks of you, and why we leave it out.
The short version
- What it is
- A strict, staged gut diet built on meat stock, fermented foods and animal fat, with no grains, sugar or starchy vegetables, for about two years.
- Good for
- Getting people to cook from scratch. That's about it, as far as evidence goes.
- Bad at
- Proof. Children's nutrition. Raw milk safety. Your weekends.
- Evidence
- None. We found no published controlled trial.
- Our take
- Not in our plan. The home cooking is fine. The promises are not.
What the GAPS diet actually is
GAPS stands for Gut and Psychology Syndrome, a term coined by Dr Natasha Campbell-McBride. Her website lists autism, ADHD, dyslexia, dyspraxia, depression, OCD, bipolar disorder, schizophrenia, epilepsy and eating disorders under it, plus a second list of physical problems from asthma to IBS. It calls the GAPS diet the "baseline treatment" for all of them.1
"Gut and Psychology Syndrome" is her label, not a diagnosis your doctor will recognise. That matters, because the whole diet rests on it.
The food rules come from the Specific Carbohydrate Diet. Campbell-McBride says her lists of allowed and banned foods are built on SCD research and clinical experience.2 She then added her own layers:
- The Introduction Diet: a staged start, low in fibre, built on meat stock and soups, meant to "heal and seal" the gut.1
- Full GAPS: about 85% of daily food from meat, organ meat, fish, stock, eggs, fermented dairy and vegetables, lots of animal fat, everything cooked at home. Followed for about two years, sometimes longer.1
- Extras: raw milk introduced later (shop milk is out) and fresh juices.2
There's also a no-plant version (basically carnivore) and a ketogenic version.1
How it works in your body
The theory: a damaged gut and the wrong gut bacteria let toxins into the blood, and those toxins affect the brain. Heal the gut with broth, fat and fermented food, and brain and behaviour problems improve.
Researchers are studying links between gut bacteria and the brain, and that's worth doing. But "the gut is involved" is a long way from "this specific diet treats autism or schizophrenia". Nobody has shown the second step.
And one part of the theory should worry you. When things get worse on the diet, the FAQ explains regression as "die-off" and detoxification.2 If getting better proves the diet works, and getting worse also proves the diet works, nothing can ever prove it doesn't. That's not a theory. That's a trap.
What you eat, what you don't
Eat
- Meat stock, bone broth, soups
- Meat, organ meat, fish, eggs
- Animal fats, butter, ghee, coconut oil, olive oil
- Fermented vegetables and fermented dairy
- Non-starchy vegetables, well cooked
- Fruit, nuts and honey, later and in small amounts
Forget it
- All grains: bread, rice, noodles, oats
- Sugar and all processed carbohydrates
- Potatoes and sweet potatoes, for most of the diet
- Most legumes, at least for a long time
- Shop-bought pasteurised milk
- All processed food
Alcohol on the GAPS diet
The GAPS FAQ allows a few drinks for adults: mead made with honey rather than sugar, and tequila occasionally and in small amounts, if nothing has been added.2 Obviously none of this applies to the many children put on GAPS.
OK, now and then
- Tequila, neat or with soda water and lime
- Honey-only mead, small glass
Not on GAPS
- Beer: it's grain
- Cocktails, liqueurs, anything with sugar
- "Diet" mixers: sweeteners are on our never list anyway
50 Club: a small glass of dry wine or a gin with soda water, with food, not on an empty stomach.
All the details are in our alcohol guide.
What it's good for, with proof
The proof for GAPS itself
We searched for published controlled trials of the GAPS diet, for autism or anything else. We didn't find one. The website presents GAPS as established treatment, but cites no studies for it.1
The closest relative didn't win either
GAPS is built on the Specific Carbohydrate Diet. In the biggest trial of the SCD, 194 adults with Crohn's disease, it did no better than a Mediterranean diet.3 That's a gut disease, not a brain condition, and still no edge.
Diets for autism in general
A systematic review for the American Academy of Pediatrics looked at nutritional and dietary therapies for autistic children, including gluten-free and casein-free diets. The verdict: little evidence to support any of them. Studies were small and short.4
The uncomfortable truth
"GAPS can heal autism." There's no evidence for that. No published trial has tested GAPS for autism, and a systematic review of diets for autistic children found little evidence for any of them.4 Autistic people and their families deserve support that works and honest information, not a two-year diet presented as a treatment.
Let's be clear about who's at fault here. Parents who try GAPS are doing what parents do: looking hard for anything that might help their child. That's love, not foolishness. The problem is a protocol that promises a lot, tests nothing, and explains every setback as proof it's working.
If an autistic child has gut problems, like constipation or pain, those deserve a proper medical look, the same as for any child. A paediatrician or gastroenterologist can test for actual causes. That's the route, not a theory.
The risks
- Raw milk. Europe's food safety authority links raw drinking milk to Campylobacter, Salmonella, toxin-producing E. coli and other infections. Children, pregnant people, older people and anyone with weak immunity are at higher risk.5 GAPS tells families never to use pasteurised milk.2 That's backwards.
- Children's nutrition. Autistic children are, on average, already about five times more likely to have feeding problems than other kids, and tend to get less calcium and protein.6 Taking away grains, most legumes and normal milk on top of that is a real risk.
- Bones. In one study of autistic boys, those on casein-free diets had thinner bone than boys on unrestricted diets.7 Restricting dairy in a growing child needs a plan.
- Missing real problems. Explaining symptoms as "die-off" can delay a doctor's visit for something that needs treatment.
- Two years. Cooking stock and fermenting at home, no school canteen, no hawker centre, no Kindergeburtstag cake. A huge load on families, for an unproven result.
Allergies: watch the staples
GAPS leans on several major allergens. A child with allergies on GAPS can end up with very little left to eat.
| GAPS staple | Allergen (EU list of 14)8 | Swap |
|---|---|---|
| Kefir, yoghurt, butter, ghee, raw milk | Milk | Pasteurised alternatives if tolerated; otherwise a dietitian's calcium plan |
| Eggs, egg-yolk recipes | Eggs | Fish, meat |
| Fish, fish stock | Fish | Chicken or beef stock |
| Prawns, shellfish soups | Crustaceans, molluscs | Fish or chicken |
| Nut flour baking, nut butters | Tree nuts | Seeds, if tolerated |
| Stock and soups with celery | Celery | Carrot, onion, herbs |
Don't do the GAPS diet if you…
- want to use it to treat autism, ADHD or a mental health condition
- plan to put a child on it without a paediatrician or dietitian
- are pregnant or breastfeeding (raw milk is a serious risk)
- have ever had an eating disorder
- are underweight, or have a weak immune system
- would stop medication or therapy because of it
Healthen me asks about all of these and gives you a different plan if any apply.
How we use the GAPS diet in your plan
We don't. GAPS is not part of our plan, and here's why, bluntly: the syndrome isn't a recognised diagnosis, the diet has no published trials, it pushes raw milk, and it's often aimed at children who can least afford the nutrient gaps.
What's good in it is already in our plan anyway: home cooking, soups, fish, eggs, vegetables and fermented foods like sauerkraut, kimchi and pasteurised yoghurt. Our plan is for adults, and Healthen me sends anyone under 18 to a gentle plan and a doctor.
This article is general information, not medical advice. If you have a medical condition or take medication, talk to your doctor before changing how you eat.
Sources
- Campbell-McBride N. Gut and Psychology Syndrome, official website: home page and "GAPS Diet" page. gaps.me/gaps-diet.php (accessed 1 Nov 2026)
- Campbell-McBride N. GAPS frequently asked questions. gaps.me/faqs.php (accessed 1 Nov 2026)
- Lewis JD, Sandler RS, Brotherton C et al. A randomized trial comparing the Specific Carbohydrate Diet to a Mediterranean diet in adults with Crohn's disease. Gastroenterology 2021;161(3):837–852.e9. doi.org/10.1053/j.gastro.2021.05.047
- Sathe N, Andrews JC, McPheeters ML, Warren ZE. Nutritional and dietary interventions for autism spectrum disorder: a systematic review. Pediatrics 2017;139. doi.org/10.1542/peds.2017-0346
- EFSA Panel on Biological Hazards (BIOHAZ). Scientific opinion on the public health risks related to the consumption of raw drinking milk. EFSA Journal 2015;13(1):3940. doi.org/10.2903/j.efsa.2015.3940
- Sharp WG, Berry RC, McCracken C et al. Feeding problems and nutrient intake in children with autism spectrum disorders: a meta-analysis and comprehensive review of the literature. Journal of Autism and Developmental Disorders 2013;43:2159–2173. doi.org/10.1007/s10803-013-1771-5
- Hediger ML, England LJ, Molloy CA et al. Reduced bone cortical thickness in boys with autism or autism spectrum disorder. Journal of Autism and Developmental Disorders 2008;38:848–856. doi.org/10.1007/s10803-007-0453-6
- Regulation (EU) No 1169/2011 on food information to consumers, Annex II (the 14 allergens). eur-lex.europa.eu/eli/reg/2011/1169/oj