If you have an autoimmune disease or a metabolic or digestive health condition, you may need to avoid foods that trigger allergies or cause your condition to flare up with symptoms. For some autoimmune diseases, you have to eliminate foods or ingredients. Otherwise, you won’t experience relief from your symptoms, and your gut cannot heal. The AIP diet is very restrictive, so you may want to eliminate foods one at a time as your body adjusts.

 The AIP diet consists of two main phases.

1- The 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.

During this phase, foods like grains, legumes, nuts, seeds, nightshade vegetables, eggs, and dairy are completely avoided.

Tobacco, alcohol, coffee, oils, food additives, refined and processed sugars, and certain medications, such as non-steroidal anti-inflammatory drugs (NSAIDs) should also be avoided. Examples of NSAIDs include ibuprofen, naproxen, diclofenac, and high-dose aspirin.

On the other hand, this phase encourages the consumption of fresh, nutrient-dense foods, minimally processed meat, fermented foods, and bone broth. It also emphasizes the improvement of lifestyle factors, such as stress, sleep, and physical activity.

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 30–90 days, but some may notice improvements as early as within the first 3 weeks.

2- The 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.

During this phase, foods should be reintroduced one at a time, allowing for a period of 5–7 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 

Foods that are well tolerated can be added back into the diet, while those that trigger symptoms should continue to be avoided. Keep in mind that your food tolerance may change over time.

As such, 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.

• Step 1. Choose one food to reintroduce. Plan to consume this food a few times per day on the testing day, then avoid it completely for 5–6 days.
• Step 2. Eat a small amount, such as 1 teaspoon of the food, and wait 15 minutes to see if you have a reaction.
• Step 3. If you experience any symptoms, end the test and avoid this food. If you have no symptoms, eat a slightly larger portion, such as 1 1/2 tablespoons, of the same food and monitor how you feel for 2–3 hours.
• Step 4. If you experience any symptoms over this period, end the test and avoid this food. If no symptoms occur, eat a normal portion of the same food and avoid it for 5–6 days without reintroducing any other foods.
• Step 5. If you experience no symptoms for 5–6 days, you may reincorporate the tested food into your diet, and repeat this 5-step reintroduction process with a new food.

It’s best to avoid reintroducing foods under circumstances that tend to increase inflammation and make it difficult to interpret results. These include during an infection, following a poor night’s sleep, when feeling unusually stressed, or following a strenuous workout.