AIP Diet: Evidence, Risks and Safer Decisions

The AIP diet is a restrictive eating approach with limited clinical evidence. This guide explains its food rules, research findings, nutritional trade-offs and questions to discuss before trying it. ¹

Educational information checked against the listed sources on 14 October 2026. Individual dietary decisions need personal medical and nutrition advice. Read our medical disclaimer.

What is the AIP diet?

AIP stands for autoimmune protocol. It usually begins with a broad elimination phase, followed by reintroduction and a more individualized eating pattern. Its proposed purpose is to explore whether foods relate to symptoms. Proposed explanations involving the gut or immune system are hypotheses; they do not establish that removing these foods treats an autoimmune disease. Different versions of the protocol make a single universal food list misleading. ¹

How the commonly described food rules work

A traditional, core-style AIP elimination phase commonly excludes grains, legumes, dairy, eggs, nuts, seeds, nightshade vegetables, coffee and alcohol. Nightshades include tomatoes, peppers, aubergines or eggplants, and white potatoes. Commonly included foods are meat, poultry, fish, fruits, many other vegetables, sweet potatoes and selected oils. These categories describe the protocol; they are not a prescription for every reader. Exclusion does not prove that a food causes inflammation. Check the exact version being proposed with a dietitian, because recipes and online lists can use different rules. ^{1, 2}

What the clinical research actually shows

Inflammatory bowel disease: an encouraging small pilot

A 2017 AIP study had a final cohort of fifteen adults with active Crohn’s disease or ulcerative colitis. Eleven met the study’s symptom-based criteria for clinical remission by week six. That finding is worth investigating, but it cannot establish that AIP caused the improvement. The study had no randomized comparison group, seven participants were using biologic medicines, and identified nutritional deficiencies were treated. C-reactive protein did not change significantly; the reduction in average faecal calprotectin also did not meet statistical significance. Only seven participants had follow-up endoscopy. The program included support and other lifestyle advice, so it did not isolate food removal from everything else that changed. These details matter when a headline presents the remission percentage as an expected personal success rate. The trial supports further research, not stopping effective IBD treatment or assuming that symptom improvement proves intestinal healing. ³

Hashimoto’s thyroiditis: symptoms and thyroid tests differ

The 2019 Hashimoto’s pilot enrolled seventeen women in a supported diet and lifestyle program; sixteen completed symptom questionnaires. Participants reported improvements in quality of life and symptom burden. However, the investigators did not find statistically significant changes in thyroid function tests or thyroid antibodies. The study was single-arm, meaning there was no separate comparison group receiving otherwise similar attention without AIP. Coaching, community support, changes in daily routines and expectations may have influenced what participants reported. An improvement in fatigue or wellbeing is meaningful to the person experiencing it, but it is a different outcome from restoring thyroid hormone production. The study cannot tell us which element of the program mattered most, whether benefits persisted, or whether the results apply to all people with Hashimoto’s disease. It should not be presented as evidence that diet can replace prescribed thyroid hormone. ⁴

A later thyroid study reported mixed laboratory findings

A 2023 study enrolled twenty-eight people with Hashimoto’s disease in an AIP dietary intervention; twenty completed it. Fewer participants reported malaise, while changes in thyroid tests were mixed. Free thyroid hormone measurements and TSH decreased but remained within the reference range. Thyroglobulin antibodies decreased slightly, whereas thyroid peroxidase antibodies increased significantly. Participants also lost weight, suggesting that energy intake did not match expenditure. A before-and-after observation cannot reliably separate the diet’s effect from other influences or ordinary variation over time. The antibody finding is particularly important because a simplified claim that AIP uniformly lowers thyroid antibodies would misrepresent this study. Nor should the weight change automatically be described as a benefit. People considering restriction need enough food and an agreed way to check nutritional adequacy, alongside ordinary clinical follow-up for their thyroid condition. ⁵

Rheumatoid arthritis: a 2026 feasibility study

A small rheumatoid arthritis pilot published in 2026 adds to the research, but does not settle the question. Nine adults completed four weeks on their usual diet followed by eight weeks of AIP. Seven reported improvements across patient-reported measures by the end of the intervention. The study was open-label and used a single-arm design, so participants knew which diet they were following and there was no randomized parallel control group. Such a study can explore whether an intervention is workable and identify signals worth testing in a larger trial. It cannot establish that the diet prevents joint damage, replaces disease-modifying medicines or will produce the same response in a broader population. Longer, controlled research is needed to understand effectiveness, practical burden and safety. Personal reports of feeling better should be discussed alongside the rheumatology team’s assessment of disease activity. ⁶

Current IBD consensus remains cautious

The European Crohn’s and Colitis Organisation’s 2025 dietary consensus states that evidence is insufficient to support AIP as induction therapy for Crohn’s disease or ulcerative colitis. Induction therapy means treatment intended to bring active disease under control. A promising observation is not the same as an established treatment option. If an AIP plan is being proposed during an active flare, ask the gastroenterology team how it fits the condition’s treatment and nutrition needs. The consensus does not justify delaying the treatment already recommended for active inflammation. ⁷

Start with the diagnosis and your existing treatment

IBD nutrition has more than one purpose

The American Gastroenterological Association recommends a Mediterranean-style pattern for the overall health and wellbeing of people with IBD, adapted to individual circumstances. Its 2024 clinical practice update notes that no diet has consistently reduced flare rates in adults with IBD. That is different from saying nutrition is unimportant: adequate nourishment and selected, supervised nutrition therapies can be important parts of care. The update discusses approaches such as exclusive enteral nutrition and the Crohn’s disease exclusion diet in particular settings; these are distinct interventions and should not be relabelled as AIP. The appropriate choice depends on the diagnosis, disease activity, previous surgery and nutritional status. Ask the team what the proposed diet is meant to achieve: manage symptoms, correct a deficiency, support overall health or treat active disease. Different goals need different evidence and different monitoring. ⁸

Rheumatoid arthritis care still needs disease control

The American College of Rheumatology’s guideline on integrative interventions conditionally recommends a Mediterranean-style diet for people with rheumatoid arthritis. It conditionally recommends against other formally defined diets for managing the condition because consistent, clinically meaningful benefit has not been established. The guideline treats these approaches as additions to disease-modifying treatment. A conditional recommendation also leaves room for discussing individual preferences and circumstances; it does not turn an elimination diet into a proven substitute. Bring any proposed eating plan to the rheumatology visit, especially if it comes with instructions to stop medicines. Pain, tiredness and daily functioning are useful outcomes to discuss, while the team also considers inflammation and the risk of damage. A diet that feels manageable and provides adequate nutrition can be evaluated without changing the treatment plan on the basis of an online testimonial. ⁹

Thyroid medicine and meal timing need a separate plan

When Hashimoto’s disease causes hypothyroidism, levothyroxine replaces hormone that the thyroid cannot make adequately. Diet should not be used to stop or adjust that medicine without the prescriber. Foods and supplements can affect absorption, including products containing calcium or iron, so a major change in breakfast habits or supplement use is worth mentioning. Follow the timing instructions for your particular medicine rather than borrowing another person’s schedule. The clinician can decide whether a change warrants repeat blood tests. Feeling less tired does not establish that hormone replacement is no longer needed, and continuing symptoms deserve review rather than increasingly severe food restrictions. Keep a clear list of medicines, supplements and their usual timing for that appointment. Our hypothyroidism diet guide discusses everyday food planning alongside treatment. ¹⁰

Discuss coeliac testing before removing gluten

If coeliac disease is a possibility, speak with a clinician before starting a gluten-free elimination diet. Removing gluten can affect blood tests and intestinal biopsy findings, making the diagnosis harder to establish. Symptoms alone cannot reliably distinguish coeliac disease from other digestive conditions. Tell the clinician about relatives with coeliac disease, relevant medical history and how much gluten you currently eat. If you have already stopped gluten, explain when and why; do not improvise a gluten challenge, particularly if allergy is also suspected. A confirmed coeliac diagnosis requires its own long-term gluten-free treatment plan. It is not a reason to eliminate every food category on an AIP list. Our guide to wheat allergy, coeliac disease and testing explains the terminology. ¹¹

Reintroduction cannot diagnose or rule out food allergy

A medically supervised oral food challenge is a diagnostic procedure, sometimes used when the clinical history and allergy tests leave uncertainty. It is performed with trained staff and treatment available if a reaction occurs. An AIP food diary or a home experiment does not provide that safeguard. Anyone with a known food allergy or a history suggesting an immediate allergic reaction should discuss reintroduction with an allergy specialist before trying the food. Explain what happened, how soon it started and what treatment was needed. Do not use a small taste as proof that a larger portion will be safe. The allergist can decide whether a challenge is appropriate and provide the specific instructions. ¹²

Commercial IgG panels do not supply an AIP exclusion list

Tests marketed as broad food-sensitivity panels often measure IgG antibodies to many foods. The American Academy of Allergy, Asthma and Immunology explains that these tests have not been scientifically established for diagnosing the problems they claim to identify. IgG may reflect normal exposure to a food, and some IgG responses are associated with tolerance. A coloured report listing dozens of foods therefore should not be treated as evidence that each food causes disease or must be removed. If you already have such a report, bring it to a qualified clinician rather than expanding restrictions yourself. Describe the actual symptoms and their timing so that the assessment begins with the clinical problem. Appropriate testing is chosen to answer a specific question; an impressive number of results does not make an unvalidated test more informative. ¹³

Persistent digestive symptoms may need a different approach

Irritable bowel syndrome and inflammatory bowel disease are different conditions, even though their abbreviations sound similar. For adults with diagnosed IBS whose symptoms persist after general advice, NICE recommends dietary guidance from a professional with relevant expertise. That can include a structured exclusion approach, such as a low-FODMAP diet, where appropriate. It is not the same as AIP, and combining several restrictive plans can make everyday eating much harder. The choice should follow assessment of the symptoms rather than the assumption that more exclusions mean a more effective treatment. Ask what the initial trial is testing, what support is available and when its usefulness will be reviewed. Keep the explanation in terms of the diagnosed condition and the individual goal. A change that helps bloating does not, by itself, establish that an autoimmune disease has improved. ²⁴

Check what the replacement diet will provide

Calcium after removing dairy

Dairy is a major calcium source for many people, so removing it needs a deliberate replacement plan. Calcium contributes to bone health and other normal body functions. Canned sardines or salmon with edible bones and vegetables such as kale and bok choy provide some calcium. Fortified drinks can help, although the amount varies and some products may conflict with the particular elimination rules being followed. Read the label rather than assuming a milk substitute has the same nutritional profile as milk. A dietitian can compare the foods you actually eat with the requirement for your age and circumstances. Supplements may be useful when needed, but the type, dose and medicine interactions require consideration. Calcium carbonate, for example, can interfere with levothyroxine absorption. Ask the pharmacist about separation from your own prescription rather than adding a supplement at the same time each morning. ¹⁵

Vitamin D is not guaranteed by a colourful plate

Very few foods naturally provide much vitamin D. Fatty fish are useful sources, while fortified foods provide a substantial share of intake in some countries. Excluding fortified milk, cereals or plant drinks can remove sources someone previously relied on. Vitamin D helps calcium absorption, and people with conditions that impair fat absorption may have additional difficulty maintaining adequate levels. These facts support checking an individual’s needs; they do not establish that high-dose vitamin D treats autoimmune disease. Tell the clinician about all supplements already being taken, including combination products, so overlapping doses are visible. If testing or supplementation is recommended, follow the agreed dose and review plan. More is not automatically better, and excessive supplementation can be harmful. A broad list of permitted foods is less useful than checking whether the person’s actual weekly meals cover the nutrients they need. ¹⁶

Iodine needs care, particularly around thyroid disease

Iodine is needed to make thyroid hormones, but both inadequate and excessive intake can cause problems. Fish and other seafood, dairy products, eggs and iodized salt are common sources. When several usual foods disappear from the menu, review what remains rather than assuming the restriction is nutritionally neutral. Sea salt and other specialty salts are not necessarily iodized; the label matters. At the same time, kelp or other iodine supplements are not a safe automatic solution. The amount of iodine in seaweed varies greatly, and some people are especially sensitive to excessive intake. Pregnancy and breastfeeding change iodine requirements, adding another reason for individualized advice. Discuss the complete diet and any supplements with the clinician or dietitian. The aim is appropriate intake, not maximizing iodine because it is associated with thyroid function. ¹⁷

Iron: assess the cause of tiredness

Iron is used to make haemoglobin, the protein in red blood cells that carries oxygen. Meat, seafood and poultry provide iron; beans, fortified cereals and other plant foods contribute too. Eliminating several familiar sources changes the practical question from whether iron exists somewhere on the allowed list to whether enough is eaten regularly. People with heavy menstrual bleeding, pregnancy or gastrointestinal disorders can have additional reasons for low iron. Fatigue alone cannot identify a deficiency, so seek assessment rather than starting a high-dose product solely on the basis of symptoms. Iron supplements can cause digestive side effects and interact with medicines, and excess iron can be harmful. Keep them away from children. When treatment is prescribed, ask how the cause will be investigated and when response will be checked, rather than viewing supplementation as proof that the diet is complete. ¹⁸

Vitamin B12 and already limited eating patterns

Vitamin B12 supports normal nerve function and blood-cell formation. It occurs naturally in animal foods, while some foods are fortified. People who avoid animal products need reliable alternative sources, and difficulty absorbing B12 can also lead to deficiency even when intake appears adequate. This matters when considering AIP on top of a vegetarian, vegan or otherwise limited diet: a food list that works for another person may leave very few suitable choices. B12 deficiency can cause tiredness, anaemia and neurological symptoms, so new tingling, balance problems or continuing fatigue deserve medical attention rather than assumptions about a dietary adjustment. A clinician can decide which tests and treatment are appropriate. Review existing fortified foods and supplements before removing them. The goal of a nutrition assessment is to identify what the individual needs, including absorption problems that a more restrictive menu would not solve. ¹⁹

Food symptoms and food texture deserve separate attention

The Crohn’s & Colitis Foundation distinguishes foods that provoke digestive symptoms from foods that necessarily worsen inflammation. A food may be difficult to tolerate without being a universal inflammatory trigger. Preparation and texture can also matter: peeled, cooked or blended produce may suit someone differently from large portions of raw vegetables. People with intestinal narrowing or strictures need specific advice, because a generic instruction to increase rough, fibrous foods may be unsuitable. Discuss the pattern with the IBD team before making major changes. Note the food, portion and preparation as well as the symptom, instead of permanently banning a whole category after one difficult meal. The purpose is to preserve as much variety and nourishment as possible while adapting to the person’s disease and tolerance. Persistent or worsening symptoms still need clinical assessment rather than an expanding list of suspected foods. ²⁸

AIP food rules are not cardiovascular guidance

The American Heart Association recommends using liquid plant oils rich in unsaturated fats in place of fats high in saturated fat. Its examples include olive, canola, sunflower and other commonly available oils. Some AIP lists exclude oils that this guidance includes, which shows why protocol rules should not automatically be interpreted as established nutrition advice. Coconut oil is also not interchangeable with olive oil simply because both appear on a recipe website. When choosing substitutions, consider the overall pattern, your medical history and what you enjoy cooking. Ask a dietitian to explain the nutritional reason for a change instead of relying on whether an ingredient is labelled compliant. Practical choices should fit heart health and other existing care goals as well as the immediate dietary experiment. No single cooking oil establishes whether a meal is suitable for an individual with autoimmune disease. ²⁹

Who needs extra caution before restriction?

Unintentional weight loss and low intake

Nutritional risk depends on more than appearance or current body size. NICE guidance considers recent unintentional weight loss, body mass index, reduced intake and the likelihood that poor intake will continue. Someone who is already struggling to eat enough needs assessment before further food exclusions. Do not assume weight loss during a restrictive diet is desirable or harmless because the original goal was symptom relief. Bring a record of usual meals, recent weight changes and any difficulty chewing, swallowing or keeping food down. A clinician or dietitian can assess energy, protein and fluid needs and decide whether nutrition support is appropriate. If intake has been very low for a prolonged period, recovery may also need medical supervision. The priority is restoring adequate nourishment safely, not proving that a person can remain within an increasingly narrow list of foods. ²⁰

Food anxiety and a shrinking range of safe foods

Eating disorders can involve severe restriction of the amount or variety of food, and they can affect people across different body sizes. Avoidant restrictive food intake disorder, for example, can include a progressively narrower range of foods without a desire to lose weight. Restriction may interfere with health, work, relationships and ordinary daily life. These problems deserve support, not praise for dietary discipline. Tell a clinician if eating is becoming frightening, meals are repeatedly skipped, or the list of foods considered safe keeps shrinking. A past eating disorder is also relevant before beginning an elimination plan. A professional assessment can help distinguish medical dietary needs from patterns that are becoming harmful and arrange suitable treatment. Keeping nutrition and psychological wellbeing in view is part of evaluating an eating plan; neither should be treated as an optional concern after the food rules have been followed. ²¹

Children need protection of growth and variety

Children should not be placed on a broad AIP elimination diet using an adult online plan. Children’s Hospital of Philadelphia advises considering the risks of elimination trials, including inadequate nutrients, weight loss and effects on growth. These concerns become more important when a child already eats a narrow range of foods or has several medically necessary exclusions. A paediatric clinician and dietitian can assess the reason for the proposed change, what will replace the removed foods and how growth and intake will be monitored. Families also need an approach that works at school, with other caregivers and during social occasions. Avoid turning a child’s symptoms into a test of willpower or insisting that every meal follow an unreviewed internet list. If a food allergy or another condition requires avoidance, use that child’s clinical plan and make sure each caregiver understands its purpose. ²²

Pregnancy requires individual nutrition advice

Pregnancy is a time to discuss major dietary changes with the maternity team. NHS guidance emphasizes varied eating to provide the nutrients needed by the pregnant person and developing baby, alongside recommended supplementation such as folic acid. A broad elimination plan can conflict with familiar sources of energy, protein and calcium, especially when nausea already limits what feels manageable. Bring the proposed food list to the appointment and explain existing exclusions, supplements and any difficulty eating. Organ meats are not a universal solution to nutritional gaps: NHS pregnancy guidance specifically advises avoiding liver. Advice about fish choices and food safety also matters. There is no need to copy someone else’s special pregnancy menu or a general AIP recipe collection. The maternity team can help adapt meals to personal preferences while addressing pregnancy-specific requirements and any underlying autoimmune condition. ²³

Diabetes medicines can make abrupt changes risky

People who use insulin or certain diabetes medicines need a plan before making large changes to carbohydrate intake or meal timing. Eating too little carbohydrate, delaying a meal or missing food can contribute to low blood glucose when medication continues to act. A restrictive food list does not remove that risk. Discuss proposed changes with the diabetes team so that eating, glucose monitoring and prescribed treatment remain coordinated. Keep the recommended treatment for low glucose available even if a diet website would classify it as excluded. Follow your own hypoglycaemia action plan and seek urgent help for severe symptoms or inability to treat safely. Do not stop insulin or alter doses simply because an eating approach is described as autoimmune-friendly. The immediate priority is a safe match between food and treatment, with changes guided by the professionals who know the individual regimen. ³⁰

A safer way to evaluate a proposed diet

Agree on a question, a review date and reintroduction

The Academy of Nutrition and Dietetics describes elimination diets as structured approaches with elimination and reintroduction phases, supported by appropriate clinical assessment. A registered dietitian can review usual intake, identify likely gaps and plan suitable substitutions. The return of foods is part of the process, not a failure to maintain discipline. Before starting, discuss which symptoms are being evaluated and when the plan will be reviewed. Reintroduction should follow the professional’s instructions and account for any known allergy or coeliac disease. A record of portions, ingredients and symptoms can help the discussion, but a single reaction should not automatically turn into lifelong avoidance. If the diet is not helping or is becoming difficult to sustain, that is useful information for the review. The objective is an adequate, workable pattern with a clear reason for each continuing restriction. ²⁷

Keep the diary simple enough to use

Choose a format you can maintain on an ordinary busy day. Record meals in plain language, including approximate portions and preparation, then add the symptom you agreed to follow and the time it occurred. Leave room for medicines, sleep, illness and unusual events so the clinician can see the surrounding circumstances. Bring the original notes to the review instead of summarizing every day as good or bad. Decide in advance how much detail feels useful and stop short of recording every sensation. A diary is a communication tool for the agreed question, not a daily judgement of how perfectly someone has eaten.

Build meals around what is genuinely workable

Start by writing down several meals you already know how to prepare. For each one, mark the ingredients that conflict with the proposed plan and discuss replacements before shopping. A familiar dinner might need one adjustment; another might be so altered that choosing a different meal is easier. Include breakfast, work lunches, snacks and the days when there is little time to cook. Make room for foods that suit your culture, budget and household rather than constructing a menu entirely from specialist recipes. Then show the actual menu to the dietitian, because a theoretical list of allowed ingredients does not reveal what you will eat. Ask whether the plan leaves realistic options at the places you normally buy food. If the answer is no, revise the plan before beginning rather than relying on willpower to bridge the gaps.

Read labels for the reason that matters

For a diagnosed food allergy, ingredient information and cross-contact precautions remain important even when a product is advertised as AIP-friendly. In the United States, FDA rules identify nine major food allergens for relevant packaged foods, including sesame. Those rules do not cover every possible allergy or every food-service situation. Advisory phrases such as may contain are voluntary, so their absence is not a guarantee that cross-contact cannot occur. Read the full label each time because ingredients can change, and follow the allergy team’s advice about uncertain products. A marketing label cannot replace the individual avoidance plan. When eating away from home, explain the actual diagnosed allergy to staff rather than assuming they know what an AIP request means. The information needed to prepare an allergy-safe meal is different from a general preference about ingredients. ¹⁴

Batch cooking still needs ordinary food safety

Cooking ahead can make a complicated menu easier, but safe handling matters, especially for people whose illness or medicines weaken their ability to fight infection. Keep raw meat, poultry and seafood separate from ready-to-eat foods, wash hands and preparation surfaces, cook food to a safe internal temperature and refrigerate promptly. FoodSafety.gov advises refrigerating perishable food within two hours, or within one hour when the temperature is above 90°F or 32°C. A food thermometer is more reliable than judging doneness by appearance. Prepare manageable amounts and label containers so that their contents and preparation dates are clear. An ingredient being fresh, natural or permitted by a diet does not make unsafe storage harmless. Ask the treating team about additional precautions relevant to immunosuppressive treatment. Food safety belongs in the plan from the first shopping trip, not only after a stomach upset. ²⁶

Supplements need their own evidence and review

An AIP program may also advertise powders, probiotics or other supplements. Evaluate those separately from the food plan. The FDA does not approve dietary supplements for safety and effectiveness before they are sold, and natural is not a guarantee of safety. Products can interact with medicines, affect laboratory tests or create problems when several supplements contain overlapping ingredients. Take the actual labels or clear photographs to a clinician or pharmacist, including the dose and how often you use each product. Ask what specific problem a supplement is intended to address and how benefit or harm would be assessed. Nutrient replacement for an identified need is different from purchasing a bundle promoted as an immune reset. Do not replace prescribed medicines with a supplement. If an adverse reaction occurs, stop the supplement and seek appropriate medical advice, with urgent care when symptoms are severe. ²⁵

Make the follow-up decision practical

At the agreed review, bring the menu, diary, questions and a realistic account of the effort involved. Describe any change in shopping costs, cooking time, shared meals and your ability to eat away from home. Ask the clinician or dietitian to write down the next step clearly: continue a defined trial, change the approach, return particular foods or investigate the symptoms further. Confirm who to contact if the plan becomes unmanageable before the next appointment. The decision should reflect the question you started with and what actually happened, rather than pressure to keep restricting because you have already invested time in the process.

If symptoms worsen, intake becomes inadequate or you lose weight unintentionally, seek clinical advice rather than extending restriction. Nutritional assessment is part of safe care. ²⁰

Frequently asked questions

Is AIP an established treatment for active IBD?

No. ECCO finds insufficient evidence to support AIP as induction treatment for Crohn’s disease or ulcerative colitis. ⁷

Should I stop gluten before coeliac testing?

Ask your clinician first; removing gluten can affect diagnostic results. ¹¹

Can I reintroduce a suspected food allergen at home?

Discuss it with an allergy specialist. Diagnostic food challenges require medical supervision. ¹²

What should I bring to a diet review?

Bring your food record, symptom timeline, medicine and supplement list, and questions about the next step.