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The autoimmune protocol diet — or AIP diet — restricts foods and ingredients thought to trigger intestinal inflammation.

As the name implies, the AIP diet is commonly recommended for people with autoimmune diseases.

While not scientifically proven, the AIP diet may offer symptom relief and improve the quality of life in some people with these conditions.

This article explains what to eat and avoid on an AIP diet and provides a sample AIP diet menu.

AIP diet

What is the AIP diet?

The AIP diet is a paleo-type diet intended to reduce inflammation and ease symptoms caused by autoimmune diseases.

Autoimmune diseases occur when the body’s immune system attacks and destroys healthy cells.

Depending on the disease and body systems affected, this can result in a range of symptoms, including (1):

  • nausea
  • abdominal pain
  • diarrhea
  • constipation
  • bloody stools
  • fatigue
  • unintentional weight loss
  • joint pain, stiffness, and swelling

While nearly 100 autoimmune diseases exist, inflammatory bowel disease, celiac disease, psoriasis, and rheumatoid arthritis are among the most common (2).

The cause of these diseases remains largely unknown, but they’re thought to be triggered by environmental factors like diet in genetically susceptible people (3).

Indeed the Western diet, also known as the standard American diet (SAD), which consists of foods high in saturated fat, refined sugar, and sodium, is thought to play a key role in the development of autoimmune diseases, especially irritable bowel disease (IBD) (4, 5).

As such, the AIP diet eliminates these foods and others that are thought to trigger inflammation in people with IBD and other types of autoimmune diseases like Hashimoto’s disease (6, 7).

AIP diet phases

The AIP diet is an extremely strict elimination diet that consists of three phases — the elimination phase, the maintenance phase, and the reintroduction phase.

Elimination phase

Foods that may trigger inflammation or dysbiosis — an imbalance in your body’s bacterial colonies — within the intestines are eliminated for six weeks in this phase.

Foods to eliminate include (6):

  • grains, such as barley, corn, rice, oats, wheat, and any products made from them like bread, pasta, and cereals
  • legumes, such as beans, peanuts, chickpeas, and lentils
  • nightshades, including white potatoes, tomatoes, eggplant, bell peppers, paprika, and cayenne pepper
  • dairy, such as milk, cheese, yogurt, and dairy desserts
  • seeds, such as chia seeds, wild rice, pumpkin seeds, pomegranate seeds, quinoa, flax seeds, and hemp seeds
  • nuts, such as cashews, hazelnuts, pecans, almonds, and pistachios
  • refined sugars, such as cookies, cakes, candy, soda, fruit juices, canned fruit, and condiments like salad dressings, ketchup, and barbeque sauce
  • industrial seed oils, such as canola, corn, cottonseed, peanut, sunflower, and safflower oil
  • food additives, such as artificial sweeteners, colorings, and preservatives
  • eggs, including egg whites
  • coffee
  • alcohol

Here’s a list of foods you can eat:

  • Proteins: fresh chicken, beef, lamb, pork, seafood, and organ meats
  • Vegetables: arugula, broccoli, cauliflower, carrots, cucumber, mushrooms, and onions
  • Fruits: apples, bananas, berries, peaches, mangoes, etc.
  • Fats: avocado oil, coconut oil, and olive oil
  • Pantry and baking: apple cider vinegar, bone broth powder, coconut sugar, and honey
  • Fermented foods: kombucha, sauerkraut, and pickled non-nighshade vegetables
  • Beverages: bone broth, fruit-infused water, and teas

It’s best to keep a journal so you can document the foods you eliminate. This will make it easier to keep track when you reintroduce them in the last phase.

Maintenance phase

During this phase, continue to eat only the foods emphasized and restrict the foods you initially eliminated.

Do this for 4–5 weeks, or until your symptoms become minimal to nonexistent.

Reintroduction phase

This phase involves reintroducing the foods you eliminated, one at a time, slowly over several days while you look for symptoms.

If you experience no symptoms after reintroducing a food, you can assume that food is not a trigger and then reintroduce the next food.

Generally, you will know whether a specific food or ingredient triggers your symptoms within minutes to 2–4 hours.

If you do experience symptoms, however, you should remove that food from your diet.

Though, complete elimination of some foods may not be necessary as you may be able to tolerate small amounts before it triggers symptoms.

Use the journal from the elimination phase to document any symptoms you experience as you reintroduce each food.

The AIP diet process, including the elimination phase, takes 12–16 weeks.

Sample AIP diet menu

Here’s a sample AIP diet menu during the elimination phase:

  • Breakfast: coconut milk yogurt with berries
  • Snack: kiwi slices and bone broth drink
  • Lunch: ground beef patties and an arugula salad drizzled with olive oil
  • Snack: roasted sweet potato and jicama fries made with olive oil
  • Dinner: baked salmon with roasted squash and broccoli

Remember to follow the elimination phase for at least six weeks.

Benefits

While limited, there is some evidence to support the AIP diet for IBD and Hashimoto’s disease.

IBD

IBD generally refers to Crohn’s disease or ulcerative colitis, conditions that involve chronic inflammation of the digestive tract.

In one study, patients with active IBD followed a 6-week elimination phase followed by a 5-week maintenance phase using the popular “standard American diet (SAD) to AIP in six” diet transition program (8).

After the 6-week elimination phase, 73% of the patients experienced significant symptom reduction and clinical remission and remained in remission during the 5-week maintenance phase.

Levels of two reliable markers of inflammation — C-reactive protein (CRP) and fecal calprotectin (FC) — were also decreased after weeks 6 and 11 compared with baseline, albeit not significantly.

Unfortunately, this study was a pilot study and didn’t assess the reintroduction of food after the maintenance phase.

Hashimoto’s disease

Hashimoto’s disease — also known as Hashimoto’s thyroiditis — is the most common cause of underactive thyroid or hypothyroidism in developed countries (9).

It predominantly affects white females.

In one study, 16 women with Hashimoto’s disease followed the SAD to AIP in six diet, which involved a 6-week elimination phase followed by a 4-week maintenance phase (10).

After the 10 week study period, the women reported significant improvements in quality of life measures and symptoms.

The women also experienced significant decreases in CRP and body weight compared with their baseline measurements, despite no changes in thyroid levels.

What’s more, the women were able to decrease their dose of medication used to manage Hashimoto’s disease.

Like the study on people with IBD, the researchers did not assess the reintroduction phase.

Downsides

Despite the promising results from studies, the AIP diet has several downsides to consider.

The biggest downside is its extreme restrictiveness during the elimination phase.

While necessary, eliminating multiple food groups for 6 weeks and preparing AIP-compliant meals can be very challenging — even for the most disciplined.

Although the studies examining the effects of the AIP diet in patients with IBD and Hashimoto’s disease had a low dropout rate, they received significant education, support, and accountability from registered dietitians and health coaches.

Without this support, it can be difficult — if not impossible — to adhere to and properly follow the AIP diet.

The diet’s restrictiveness can also make it difficult to get enough nutrients without taking a multivitamin and multimineral supplement.

And although the risk of adverse side effects from following the AIP diet remains low, studies have reported worsening symptoms in patients (11).

Resulting from an increase in meat and raw vegetables, one patient even experienced a small bowel obstruction that required hospitalization (11).

Other patients have also experienced increases in triglycerides or LDL “bad” cholesterol (8).

That said, if you plan to try the AIP diet for symptom relief, it’s best to do so under the supervision of your doctor and with support and education from a registered dietitian to ensure diet adherence and safety.

The bottom line

The AIP diet is a paleo-type diet that eliminates foods thought to trigger inflammation or gut dysbiosis in people with autoimmune diseases.

It consists of a 6-week elimination phase, followed by a 4–5 week maintenance phase, and finally a reintroduction phase.

While limited, some evidence has demonstrated improvements in symptoms and quality of life in people with IBD and Hashimoto’s disease who follow the AIP diet.

However, the AIP diet can be difficult to follow safely, correctly, and long enough to experience symptom relief without supervision from your doctor and counseling from a registered dietitian.


Gavin Van De Walle, MS, RD, LN
Gavin Van De Walle, MS, RD, LN

Gavin Van De Walle holds a master's degree in human nutrition and bioenergetics. He is a registered dietitian who aims to arm the public with evidence-based nutrition recommendations so they can make their own educated and informed health decisions.