- The AIP diet eliminates foods that may trigger inflammation and reintroduces them gradually.
- It aims to reduce symptoms of autoimmune diseases such as lupus, IBD, and rheumatoid arthritis.
- Some people report symptom relief, but research on the AIP diet remains limited.
An Autoimmune Protocol (AIP) diet plan can be similar to the paleo diet but is usually more strict. It primarily involves eliminating certain foods that may cause inflammation and reintroducing them gradually once symptoms improve.
About the AIP diet
The Autoimmune Protocol (AIP) diet is an elimination diet designed for people with autoimmune disorders.
A healthy immune system produces antibodies that attack foreign or harmful cells. In people with autoimmune disorders, however, the immune system may mistakenly attack healthy cells and tissues instead.
This can lead to symptoms such as joint pain, fatigue, abdominal pain, diarrhea, brain fog, and tissue and nerve damage.
Examples of autoimmune disorders include rheumatoid arthritis (RA), lupus, inflammatory bowel disease (IBD), type 1 diabetes, and psoriasis (1).
The AIP diet resembles the paleo diet, both in the types of foods allowed and avoided, as well as in the phases that comprise it. Due to their similarities, many consider the AIP diet an extension of the paleo diet — though AIP may be seen as a stricter version of it.
The AIP diet consists of two main phases.
Elimination phase
The first phase is an elimination phase that involves the removal of foods and medications believed to cause gut inflammation, imbalances between levels of good and bad bacteria in the gut, or an immune response (
What to do during the elimination phase
Some things to avoid during this phase are:
- foods like grains, legumes, nuts, seeds, nightshade vegetables, eggs, and dairy
- tobacco, alcohol, coffee, oils, food additives, refined and processed sugars (1)
- certain medications, such as nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen (Advil), naproxen (Aleve), diclofenac (Voltaren), and high dose aspirin (Bayer extra strength)
The length of the elimination phase of the diet varies, as it’s typically maintained until a person feels a noticeable reduction in symptoms. On average, most people maintain this phase for 30 to 90 days, but some may notice improvements as early as within the first 3 weeks.
Reintroduction phase
Once a measurable improvement in symptoms and overall well-being occurs, the reintroduction phase can begin. During this phase, the avoided foods are gradually reintroduced into the diet, one at a time, based on the person’s tolerance.
The goal of this phase is to identify which foods contribute to a person’s symptoms and reintroduce all foods that don’t cause any symptoms while continuing to avoid those that do. This allows for the widest dietary variety a person can tolerate.
What to do during the reintroduction phase
- Introduce foods one at a time, allowing for a period of 5 to 7 days before reintroducing a different food. This allows a person enough time to notice if any of their symptoms reappear before continuing the reintroduction process (1).
- Foods that are well tolerated can be added back into the diet, while those that trigger symptoms should continue to be avoided.
- Your food tolerance may change over time, so you may want to repeat the reintroduction test for foods that initially failed the test every once in a while.
Step-by-step reintroduction protocol
Here’s a step-by-step approach to reintroducing foods that were avoided during the elimination phase of the AIP diet.
Plan to consume this food a few times per day on the testing day, then avoid it completely for 5 to 6 days.
Eat a small amount of the food, such as 1 teaspoon, and wait 15 minutes to see if you have a reaction.
If you experience symptoms, end the test and avoid the food. If you have no symptoms, eat a slightly larger portion, such as 1.5 tablespoons, and monitor how you feel for 2 to 3 hours.
If you experience any symptoms over this period, end the test and avoid this food. If no symptoms occur, eat a typical portion of the same food and avoid it for 5 to 6 days without reintroducing any other foods.
If you experience no symptoms for 5 to 6 days, you may reincorporate the tested food into your diet, and repeat this 5-step reintroduction process with a new food.
Other tips on reintroducing foods
The AIP diet has strict recommendations regarding which foods to eat or avoid during its elimination phase (
List of foods to eat and avoid
Vegetables
Ex: a variety of vegetables except for nightshade vegetables and algae, which should be avoided (9)
Fresh fruit
Ex: a variety of fresh fruit, in moderation
Tubers: sweet potatoes, taro, yams, as well as Jerusalem or Chinese artichokes
Minimally processed meat
Ex: wild game, fish, seafood, organ meat, and poultry; meats should be wild, grass-fed, or pasture-raised, whenever possible
Fermented, probiotic-rich foods
Ex: nondairy-based fermented food, such as kombucha, sauerkraut, pickles, and coconut kefir; probiotic supplements may also be consumed
Minimally processed vegetable oils
Ex:olive oil, avocado oil, or coconut oil
Herbs and spices: as long as they’re not derived from a seed or a chili pepper
Vinegars
Ex: balsamic, apple cider, and red wine vinegar, as long as they’re free of added sugars
Natural sweeteners
Ex: maple syrup and honey, in moderation
Certain teas
Ex: green and black tea at average intakes of up to 3 to 4 cups per day
Bone broth
Despite being allowed, some protocols further recommend that you moderate your intake of salt, saturated and omega-6 fats, natural sugars, such as honey or maple syrup, as well as coconut-based foods.
Depending on the AIP protocol at hand, small amounts of fruit may also be allowed. This usually amounts to a maximum intake of 10 to 40 grams of fructose per day, or the equivalent of about 1 to 2 portions of fresh fruit.
Some protocols further suggest moderating your intake of high glycemic fruits and vegetables, including dried fruit, sweet potatoes, and plantain.
The glycemic index (GI) is a system used to rank foods on a scale of 0 to 100, based on how much they will increase blood sugar levels, compared with white bread. High glycemic fruits and vegetables are those ranked 70 or above on the GI scale (10).
Though research on the AIP diet is limited, some evidence suggests that it may reduce inflammation and symptoms of certain autoimmune diseases.
People with autoimmune diseases often have a leaky gut, and experts believe there may be a link between the inflammation they experience and the permeability of their gut (2, 3, 11, 12).
A healthy gut typically has a low permeability. This allows it to act as a good barrier and prevent food and waste remains from leaking into the bloodstream.
However, a highly permeable or leaky gut allows foreign particles to crossover into the bloodstream, in turn, possibly causing inflammation.
In parallel, there’s growing evidence that the foods you eat can influence your gut’s immunity and function, and in some cases, possibly even reduce the degree of inflammation you experience (13, 14).
One hypothesis entertained by researchers is that by helping heal leaky gut, the AIP diet may help reduce the degree of inflammation a person experiences.
Although scientific evidence is currently limited, a handful of studies suggest that the AIP diet may help reduce inflammation or symptoms caused by it, at least among a subset of people with certain autoimmune disorders (6, 7, 15).
However, more research is needed to specifically understand the exact ways in which the AIP diet may help, as well as the precise circumstances under which it may do so (2).
To date, the AIP diet has been tested in a small group of people and yielded seemingly positive results.
For instance, in a recent 11-week study in 15 people with IBD on an AIP diet, participants reported experiencing significantly fewer IBD-related symptoms by the end of the study. However, no significant changes in markers of inflammation were observed (15).
Similarly, a small study had people with IBD follow the AIP diet for 11 weeks. Participants reported significant improvements in bowel frequency, stress, and the ability to perform leisure or sport activities as early as 3 weeks into the study (6).
In another study, 16 women with Hashimoto’s thyroiditis, an autoimmune disorder affecting the thyroid gland, followed the AIP diet for 10 weeks. By the end of the study, inflammation and disease-related symptoms decreased by 29% and 68%, respectively.
Participants also reported significant improvements in their quality of life, despite there being no significant differences in their measures of thyroid function (7).
Although promising, studies remain small and few. Also, to date, they have only been performed on a small subset of people with autoimmune disorders. Therefore, more research is needed before strong conclusions can be made.
The AIP diet is considered an elimination diet, which makes it very restrictive and potentially hard to follow for some, especially in its elimination phase.
The elimination phase of this diet can also make it difficult for people to eat in social situations, such as at a restaurant or friend’s house, increasing the risk of social isolation.
It’s also important to note that there’s no guarantee that this diet will reduce inflammation or disease-related symptoms in all people with autoimmune disorders.
However, those who experience a reduction in symptoms following this diet may be reticent to progress to the reintroduction phase, for fear it may bring the symptoms back.
This could become problematic, as remaining in the elimination phase can make it difficult to meet your daily nutrient requirements. Therefore, remaining in this phase for too long may increase your risk of developing nutrient deficiencies, as well as reduced health over time.
This is why the reintroduction phase is crucial and should not be skipped.
If you’re experiencing difficulties getting started with the reintroduction phase, consider reaching out to a registered dietitian or other medical professional knowledgeable about the AIP diet for personalized guidance.
The AIP diet is designed to help reduce inflammation, pain, or other symptoms caused by autoimmune diseases. As such, it may work best for people with autoimmune diseases, such as lupus, IBD, celiac disease, or rheumatoid arthritis.
Autoimmune diseases cannot be cured, but their symptoms may be managed. The AIP diet aims to help you do so by helping you identify which foods may be triggering your specific symptoms.
Evidence regarding the efficacy of this diet is currently limited to people with IBD and Hashimoto’s disease.
However, based on the way in which this diet is believed to function, people with other autoimmune diseases may benefit from it, too.
There are currently few downsides to trying this diet especially when performed under the supervision of a registered dietitian or other medical professional.
Seeking professional guidance prior to trying the AIP diet will help you better pinpoint which foods may be causing your specific symptoms, as well as ensure that you continue to meet your nutrient requirements as best as possible throughout all phases of this diet.
The AIP diet aims to help manage inflammation through an elimination diet. It involves removing foods from the diet, then replacing them gradually while assessing your body’s reaction.
During the elimination phase, you may consume moderate amounts of fresh fruit, bone broth, minimally processed meat, and other items.
An AIP diet avoids all processed foods, alcohol, additives, refined sugars, coffee, tea, oils, and certain medications.
In the elimination phase, a person will also avoid foods such as grains, legumes, dairy, eggs, and nightshade vegetables, but they may reintroduce these later.
After working through the elimination and reintroduction stages, you can stay on the AIP diet indefinitely. At this point, it becomes similar to the paleo diet. You won’t reintroduce any ingredients that are likely to cause you symptoms, such as refined sugars.
People on a paleo diet will focus on specific foods, such as eggs, seeds, fruits, vegetables, and minimally processed meat. The person on an AIP diet will move toward a paleo diet, but they will go through a stage of elimination and reintroduction. This means they will eat similar foods to those on a paleo diet, minus the foods that seem to cause symptoms.
The AIP diet is an elimination diet designed to help reduce inflammation or other symptoms caused by autoimmune disorders.
It’s comprised of two phases designed to help you identify and ultimately avoid the foods that may trigger inflammation and disease-specific symptoms. Research on its efficacy is limited but appears promising.
Due to its limited downsides, people with autoimmune disorders generally have little to lose by giving it a try. However, it’s likely best to seek guidance from a qualified health professional to ensure you continue to meet your nutrient needs throughout all phases of this diet.