How to Do an Elimination Diet and Why

What is an elimination diet?

An elimination diet involves removing foods from your diet you suspect your body can’t tolerate well. The foods are later reintroduced, one at a time, while you look for symptoms that show a reaction.

It lasts only 5–6 weeks and is used to help those with a sensitive gut, food intolerance, or food allergy identify which foods contribute to their symptoms (2, 3).

An elimination diet may alleviate symptoms like bloating, gas, diarrhea, constipation, and nausea.

Once you have identified a food your body can’t tolerate well, you can remove it from your diet to prevent uncomfortable symptoms.

There are many types of elimination diets, which all involve eating or removing specific foods.

However, if you have a known or suspected food allergy, you should try an elimination diet only under the supervision of a medical professional. Reintroducing a food allergen may trigger a dangerous condition called anaphylaxis (4).

If you suspect you have a food allergy, check with a doctor before starting an elimination diet. Symptoms of an allergy include rashes, hives, swelling, and difficulty breathing (5).

Summary:

An elimination diet is a short-term method that helps identify foods your body can’t tolerate well and removes them from your diet.

How does it work?

An elimination diet is divided into two phases: elimination and reintroduction.

The elimination phase

During the elimination phase of about 2-3 weeks, you remove foods you suspect trigger symptoms.

Eliminate foods you think your body can’t tolerate and foods that cause uncomfortable symptoms.

These foods include nuts, corn, soy, dairy, citrus fruits, nightshade vegetables, wheat, gluten, pork, eggs, and seafood.

During this phase, you can determine whether your symptoms are due to foods or something else. If your symptoms remain after removing the foods for 2–3 weeks, contact a doctor.

The reintroduction phase

You slowly bring eliminated foods back into your diet during the reintroduction phase.

Each food group should be introduced individually over 2–3 days while looking for symptoms. Some symptoms to watch for include:

• rashes and skin changes
• joint pain
• headaches or migraines
• fatigue
• difficulty sleeping
• changes in breathing
• bloating
• stomach pain or cramps
• changes in bowel habits

If you do not experience symptoms during the reintroduction phase, you can assume that the food group is acceptable and move on to the next group.

However, if you experience adverse symptoms like those mentioned, then you have identified a trigger food and should remove it from your diet.

The entire process, including elimination, takes roughly 5–6 weeks.

If you plan to eliminate many food groups, seek advice from your doctor or a dietitian. Eliminating too many food groups may cause a nutritional deficiency.

Summary:

An elimination diet works by removing foods you think cause discomfort. It then reintroduces them individually to check for symptoms.

What can’t you eat on an elimination diet?

The most effective elimination diets are the most restricting.

The more foods you remove during the elimination phase, the more likely it is that you will discover which foods trigger symptoms.

Foods that are commonly removed during the elimination phase include:

• Citrus fruits: Avoid citrus fruits, such as oranges and grapefruits.
• Nightshade vegetables: Avoid nightshades, including tomatoes, peppers, eggplant, white potatoes, cayenne pepper, and paprika.
• Nuts and seeds: Eliminate all nuts and seeds.
• Legumes: Eliminate all legumes, such as beans, lentils, peas, and soy-based products.
• Starchy foods: Avoid wheat, barley, corn, spelt, rye, oats, and bread. Also avoid other gluten-containing foods.
• Meat and fish: Avoid processed meats, cold cuts, beef, chicken, pork, eggs, and shellfish.
• Dairy products: Eliminate all dairy, including milk, cheese, yogurt, and ice cream.
• Fats: Avoid butter, margarine, hydrogenated oils, mayonnaise, and spreads.
• Beverages: Avoid alcohol, coffee, black tea, soda, and other sources of caffeine.
• Spices and condiments: Avoid sauces, relish, and mustard.
• Sugar and sweets: Avoid sugar (white and brown), honey, maple syrup, corn syrup, and high-fructose corn syrup, agave nectar, desserts, and chocolate.

According to a 2023 study, nightshade vegetables may potentially cause gastrointestinal reactions in irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). These vegetables may trigger uncomfortable symptoms (6).

Restrictive diets can be harmful, lead to nutritional deficiencies, and cause an adverse psychological impact, resulting in disordered eating and eating disorders. Consult with a doctor or registered dietitian before beginning an elimination diet.

If you suspect that other foods not on this list make you feel uncomfortable, consider removing them also.

Summary:

A good elimination diet is very restricting, which helps you identify as many trigger foods as possible.

What can you eat on an elimination diet?

Although an elimination diet is very restricting, there is still enough variety to make healthy and delicious meals.

Some foods you can eat include:

• Fruits: Most fruits, excluding citrus fruits.
• Vegetables: Most vegetables, excluding nightshades.
• Grains: Including rice, buckwheat, or quinoa.
• Meat and fish: Including turkey, lamb, wild game, and cold-water fish like salmon.
• Dairy substitutes: Including coconut milk and unsweetened rice milk.
• Fats: Including cold-pressed olive oil, flaxseed oil, and coconut oil.
• Beverages: Water and caffeine-free herbal teas.
• Spices, condiments, and others: Including black pepper, fresh herbs and spices (excluding cayenne pepper and paprika), and apple cider vinegar.

To stay motivated during this restrictive phase, try designing new recipes and experimenting with herbs and spices to add delicious flavor to your dishes.

Summary:

Although elimination diets are restricting, there are still plenty of food options to make healthy and delicious meals.

Other types of elimination diets

Besides the traditional elimination diet described, there are several other elimination diets.

Here are a few types of elimination diets:

• Low-FODMAPs diet: Removes FODMAPs, which are short-chain carbohydrates that some people can’t digest.
• Few foods elimination diet: This involves eating a combination of foods you don’t eat regularly. One example is the lamb and pears diet, popular in the United States, where lamb and pears are not commonly eaten.
• Rare foods elimination diet: Similar to a few foods diet, but you eat only foods you rarely eat because they are less likely to trigger your symptoms. Typical foods on a rare diet include yams, buckwheat, and starfruit.
• Fasting elimination diet: Involves strictly drinking water for up to 5 days, then reintroducing food groups. This diet should be done only with permission from a doctor because it can be dangerous.
• Other elimination diets: These include lactose-free, sugar-free, gluten-free, and wheat-free diets, among others.

Summary:

There are many types of elimination diets, including the low-FODMAPs diet, the few foods diet, the rare foods diet, fasting, and more.

Benefits of an elimination diet

Elimination diets help you discover which foods cause uncomfortable symptoms so you can remove them from your diet.

However, an elimination diet has many other benefits, including:

1. It may reduce symptoms of irritable bowel syndrome

IBS is a common gut disorder that affects around 11.2% of people worldwide (7).

Many people find that an elimination diet improves IBS symptoms such as bloating, stomach cramps, and gas.

In a 2004 study, 150 people with IBS followed either an elimination diet that excluded trigger foods or a fake elimination diet that excluded the same number of foods but not ones linked to symptoms.

People who followed the actual elimination diet reduced their symptoms by 10%. Those who best stuck to the diet reduced symptoms by up to 26% (8).

2. It may help people with eosinophilic esophagitis

Eosinophilic esophagitis (EE) is a chronic condition in which allergies trigger inflammation of the esophagus, the tube that delivers food from mouth to stomach.

People with EE have difficulty swallowing foods that are dry and dense, increasing their risk of choking.

Many studies have shown that elimination diets are effective at improving symptoms of EE (9, 10).

In a 2005 study of 146 patients with EE, more than 75% of all participants experienced significantly fewer symptoms and less inflammation through an elimination diet (11).

3. It may reduce symptoms of ADHD

Attention deficit hyperactivity disorder (ADHD) is a behavioral disorder that affects 3–5% of all children and adults.

Studies have shown elimination diets may reduce symptoms of ADHD (12, 13).

One analysis looked at 20 studies that restricted specific foods to improve ADHD symptoms. Researchers found that elimination diets helped reduce ADHD symptoms among children who were sensitive to foods (13).

However, children should not follow an elimination diet unless supervised by a medical professional.

Elimination diets restrict many essential nutrients essential for growing children. Long-term restriction could stunt their growth.

4. It may improve skin conditions like eczema

Eczema is a group of skin conditions that appear as discolored, itchy, cracked, and inflamed skin.

There are many causes of eczema, but many people find that some foods worsen their symptoms.

Several studies have found that elimination diets may reduce symptoms of eczema (14, 15).

5. It may reduce chronic migraines

Roughly 39 million people in the United States alone experience chronic migraine episodes (16).

The causes of migraine attacks are unclear, but emerging evidence points to the involvement of inflammation as a cause (17).

An elimination diet removes foods that cause inflammation and has been shown to reduce chronic migraine episodes (18, 19).

In one study, 50 patients with frequent migraine attacks followed an elimination diet for 2 months, which helped reduce the number of headache attacks during that time.

An elimination diet removes foods that cause inflammation and has been shown to reduce chronic migraines (18, 19).

Summary:

An elimination diet may benefit people with IBS, ADHD, migraine, eosinophilic esophagitis, and skin conditions like eczema.

Risks of an elimination diet

Although elimination diets help you discover foods that cause problems, they also come with risks.

For starters, elimination diets should be followed for only between 4 and 8 weeks.

Following an elimination diet for longer is not recommended because it could cause nutrient deficiencies due to eliminating some food groups.

Also, children and people with known or suspected allergies should do an elimination diet only under the supervision of a doctor (20).

Children are also more prone to severe reactions, like anaphylaxis, when reintroducing a food group. This is because their bodies can become extra sensitive to foods after avoiding them (21).

Summary:

Elimination diets can reduce the intake of essential nutrients if followed too long. Children and people with known or suspected allergies should not follow an elimination diet unless supervised by a doctor.

The bottom line

Elimination diets can help determine which foods your body can’t tolerate well.

If you’re experiencing symptoms you think may be related to diet, an elimination diet could help you discover which foods are causing them.

However, elimination diets are not for everyone. Children and adults should not try an elimination diet unless supervised by a doctor or dietitian.

Also, people with known or suspected allergies should try an elimination diet only under the supervision of a doctor.

Finally, it’s important to note that elimination diets should be done only short term because long-term restrictions may cause nutritional deficiencies and unintended disordered eating.