The AIP diet: the strictest elimination diet around. Promising, tiny studies, no cure.
The Autoimmune Protocol strips out grains, legumes, dairy, eggs, nuts, nightshades and coffee, then brings them back one by one. Some people with autoimmune disease feel better on it. Here's what the handful of studies actually show.
The short version
- What it is
- A paleo-style elimination diet for autoimmune disease: weeks of strict removal, then careful reintroduction.
- Good for
- Finding out which foods make your symptoms worse, with a team that knows your condition.
- Bad at
- Being easy, being cheap, and being proven. The biggest study had 15 people.
- Evidence
- Weak. Small, uncontrolled pilot studies.
- Our take
- A medical tool, not a lifestyle. Only with your doctor or dietitian, and never instead of your treatment.
What the AIP diet actually is
The AIP diet, short for Autoimmune Protocol, is aimed at people with autoimmune diseases: conditions where the immune system attacks the body's own tissue, such as Crohn's disease, ulcerative colitis, Hashimoto's thyroiditis or rheumatoid arthritis.
It starts from paleo (no grains, no legumes, no dairy, no refined sugar) and then goes further. In the version tested in the first IBD study, the elimination phase also removed eggs, nightshades (tomatoes, peppers, aubergine, potatoes), coffee, alcohol, nuts, seeds, refined sugars, most oils and food additives.1 That's six weeks of meat, fish, vegetables that aren't nightshades, some fruit, and a lot of home cooking.
Then comes the part people skip: reintroduction. Foods come back one at a time, and you watch what happens. The point is to end up with the widest diet you tolerate, not the narrowest one you can survive.
How it works in your body
The theory goes like this: some foods irritate the gut lining, a "leaky" gut lets more material through to the immune system, and that keeps inflammation going. Remove the suspects, let things calm down, then test them one by one.
Honest version: that's a hypothesis, not a proven mechanism. Nobody has shown that the AIP diet repairs the gut barrier in people. What the small studies measured was symptoms, quality of life and some blood markers. Some improved. Why they improved is still open: less ultra-processed food, more vegetables and fish, more attention to eating, or the extra support people got in the studies. Probably a mix.
What you eat, what you don't
This is the elimination phase. Your dietitian may adjust it for your condition.
Eat
- Fish, sardines, salmon, seafood
- Meat and poultry, including liver if you like it
- Leafy greens, broccoli, courgette, carrots, pumpkin
- Sweet potato, cassava, taro, plantain
- Fruit, in moderation
- Olive oil, avocado, coconut
- Fresh herbs, garlic, ginger
- Water and herbal tea
Forget it
- All grains: wheat, rice, oats, corn, so goodbye Brezel and nasi lemak
- Beans, lentils, chickpeas, soy, peanuts
- Milk, cheese, yoghurt, butter
- Eggs
- Nuts and seeds, including seed spices
- Tomatoes, potatoes, peppers, chilli, aubergine
- Coffee and alcohol
- Sugar, sweets, soft drinks, processed food
Alcohol on the AIP diet
Simple rule here: during the elimination phase, alcohol is out, all of it.1
OK, now and then
- Nothing during elimination
- After reintroduction: only what you and your team have tested and agreed
- Sparkling water with lime or cucumber, every day if you like
Out
- Beer: it's grain, and alcohol
- Wine, sparkling wine, spirits
- Cocktails, liqueurs, sweet mixers
- "Diet" mixers: sweeteners are on our never list anyway
Many people with autoimmune disease also take medication that comes with its own alcohol rules. With methotrexate, for example, the NHS says a drink is usually OK on a low weekly dose, and to ask your doctor first on a higher one.2
50 Club: not on a prescribed diet. Ask your doctor or dietitian what's safe for you. The general rules are in our alcohol guide.
What it's good for, with proof
Symptoms in inflammatory bowel disease, in a tiny study
Fifteen adults with active Crohn's disease or ulcerative colitis did six weeks of AIP elimination, then five weeks of maintenance. Eleven of the fifteen were in clinical remission by week six, and stayed there to week eleven.1 That sounds big. But there was no control group, no blinding, and some patients were also on new drugs. The authors themselves say it needs a proper trial.
Quality of life, same small group
In the same 15 people, scores on a standard IBD quality-of-life questionnaire improved within three weeks.3 Same cohort, so it's not extra proof, just another angle on one study.
Hashimoto's: people felt better, thyroid numbers didn't move
Sixteen women with Hashimoto's thyroiditis did a 10-week AIP programme with group coaching. Symptom scores and quality of life improved a lot, and a marker of inflammation (CRP) dropped by about 29%. Thyroid hormones and thyroid antibodies did not change.4 One author co-founded the company that ran the coaching programme. So: interesting, small, uncontrolled, and not independent.
The uncomfortable truth
"AIP heals autoimmune disease." No study shows that. The Cochrane review of diets for IBD looked at 18 randomised trials and concluded the effects of diet on Crohn's and colitis are uncertain.5 We found no randomised trial of AIP itself.
"Stricter is better." In the largest diet trial in Crohn's disease so far, 194 adults, a strict gut-healing diet did no better than a plain Mediterranean diet for symptoms.6 That was a different strict diet, not AIP. But it's a good reminder: strict doesn't automatically mean effective.
If AIP helps you, great. Use it to learn what you react to, then eat as widely as you can. Feeling better on the diet is not a reason to stop your medication.
The risks
- Nutrient gaps. No dairy, eggs, grains, legumes or nuts makes calcium, fibre and some vitamins harder to cover. In the IBD study, several people needed vitamin D or iron topped up.1 Get your blood checked.
- Avoidant eating. In one clinic, 17% of people with IBD screened positive for risk of avoidant restrictive food intake disorder (ARFID), and they were far more likely to be at risk of malnutrition.7 An elimination diet without a reintroduction plan can feed exactly that pattern.
- Losing weight you can't spare. Fewer foods often means fewer calories. If you're already underweight or ill, that's a problem.
- Delaying real treatment. Untreated inflammation damages tissue. A diet is not a replacement for the drugs your specialist prescribes.
- Cost and effort. Cooking everything from scratch, no hawker centre lunch, no quick Semmel at the bakery. Hard, socially and financially.
Allergies: watch the staples
AIP already removes most of the big allergens: cereals with gluten, eggs, milk, nuts, peanuts, soy, sesame, mustard and lupin. What's left leans on a few others.
| AIP staple | Allergen (EU list of 14)8 | Swap |
|---|---|---|
| Salmon, sardines, white fish | Fish | Poultry, lamb, beef; omega-3 needs a plan with your dietitian |
| Prawns, crab | Crustaceans | Fish or chicken |
| Mussels, squid, oysters | Molluscs | Fish or meat |
| Bone broth and soups with celery | Celery | Broth with carrot, onion and herbs |
| Dried fruit, some wines and vinegars | Sulphur dioxide and sulphites | Fresh fruit, unsulphured products |
Don't do the AIP diet if you…
- haven't got a diagnosis, or haven't talked to your doctor
- have ever had an eating disorder
- are underweight or losing weight without trying
- are pregnant or breastfeeding
- are under 18, unless a paediatric team runs it
- plan to stop or skip your medication because of it
Healthen me asks about all of these and gives you a different plan if any apply.
How we use the AIP diet in your plan
We don't. AIP is a medical elimination diet, and the elimination and the reintroduction belong with your doctor and a dietitian who knows your condition.
Healthen me asks about autoimmune and inflammatory bowel disease. If you say yes, we tell you to talk to your doctor before you change how you eat, and we don't set AIP rules for you. Our plan also contains foods AIP removes, like eggs, nuts and lentils, so it isn't suitable during an elimination phase.
What the plan can do: once your team has worked out what you don't tolerate, you can mark those foods as dislikes and the plan leaves them out. It still keeps our never list (no added sugar, no sweeteners, no soft drinks, no white bread). Fasting and Rebel Day are only for you if your doctor agrees.
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
- Konijeti GG, Kim N, Lewis JD et al. Efficacy of the Autoimmune Protocol diet for inflammatory bowel disease. Inflammatory Bowel Diseases 2017;23(11):2054–2060. doi.org/10.1097/MIB.0000000000001221
- NHS. Common questions about methotrexate. Last reviewed March 2023. nhs.uk/medicines/methotrexate/common-questions-about-methotrexate
- Chandrasekaran A, Groven S, Lewis JD et al. An Autoimmune Protocol diet improves patient-reported quality of life in inflammatory bowel disease. Crohn's & Colitis 360 2019;1:otz019. doi.org/10.1093/crocol/otz019
- Abbott RD, Sadowski A, Alt AG. Efficacy of the Autoimmune Protocol diet as part of a multi-disciplinary, supported lifestyle intervention for Hashimoto's thyroiditis. Cureus 2019;11(4):e4556. doi.org/10.7759/cureus.4556
- Limketkai BN, Iheozor-Ejiofor Z, Gjuladin-Hellon T et al. Dietary interventions for induction and maintenance of remission in inflammatory bowel disease. Cochrane Database of Systematic Reviews 2019;2:CD012839. doi.org/10.1002/14651858.CD012839.pub2
- 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
- Yelencich E, Truong E, Widaman AM et al. Avoidant restrictive food intake disorder prevalent among patients with inflammatory bowel disease. Clinical Gastroenterology and Hepatology 2022;20:1282–1289.e1. doi.org/10.1016/j.cgh.2021.08.009
- Regulation (EU) No 1169/2011 on food information to consumers, Annex II (the 14 allergens). eur-lex.europa.eu/eli/reg/2011/1169/oj