Use an Elimination Diet to Heal Your Gut, Brain, and Skin

Learn How to Simplify Elimination Diets for Better Health.

Key Takeaways:

  • Elimination diets are helpful to discover foods that cause an immune response as well as foods that may be a good match for your personal gut microbiome.
  • Elimination diets have often been found to be the most effective “tests” when it comes to identifying food intolerances [1 Trusted SourcePubMedGo to source, 2 Trusted SourcePubMedGo to source].
  • You aren’t meant to be on an elimination diet forever, but rather find the foods that work for you so you can have as diverse a diet as possible.
  • It’s best to start off with a simple elimination diet removing the most common foods that cause symptoms rather than jumping into a very restrictive one.

Elimination diets are one of the most effective ways to start getting relief from gastrointestinal symptoms, brain fog, joint pain, and chronic skin conditions. The best thing about these diets is that you can do it on your own and have agency in your own health. You don’t need fancy tests or a complicated system to do an elimination diet and start to see improvements within just a few weeks. 

So what’s the best way to follow an elimination diet, and how can it help you? Taking the simplified approach described in this article can improve symptoms and help you find your personalized nutrient-dense, gut-healthy diet. 

Elimination diet: fruits and vegetables on forks

What Is an Elimination Diet?

An elimination diet is a diagnostic and treatment tool to help discover any trigger foods that cause gastrointestinal symptoms as well as other symptoms such as headaches, rashes, joint pain, and brain fog. Following an elimination diet also provides your body with an opportunity to rest and heal.

Food Sensitivities, Intolerances, and Allergies 

An elimination diet is mainly used to discover food sensitivities and intolerances, not food allergies. When you eat a food that you’re allergic to, you typically experience an immediate immune response (like hives or trouble breathing) to the food, and you will generally have this allergy for life. These reactions are commonly found with peanuts, shellfish, and tree nuts. 

When it comes to food sensitivities and food intolerances, the reaction is often not immediate or as severe, and can happen for a few different reasons. Examples include an overactive immune response, an overgrowth of bacteria or other microbes in the gut, a lack of certain kinds of digestive enzymes, or leaky gut [1 Trusted SourcePubMedGo to source, 3 Trusted SourcePubMedGo to source, 4 Trusted SourcePubMedGo to source, 5 Trusted SourcePubMedGo to source, 6 Trusted SourcePubMedGo to source]. 

Food sensitivities and intolerances can also be temporary. When an underlying issue in the gut is resolved, you may find that you can now safely consume the food you once reacted to. 

Phases of an Elimination Diet

There are typically three phases of an elimination diet: elimination, reintroduction, and maintenance. In the elimination phase, you remove foods that are most likely to be causing physical issues and note if symptoms improve. In the reintroduction phase, you slowly add these healthy foods back into your diet, noting any recurrence of symptoms along the way, and adjusting as needed. 

Once you’ve reached the maintenance phase, your goal is to have landed on a diet that is as varied and balanced as possible, without triggering symptoms. 

Some people will re-test a food that previously caused a reaction a few months later to see if their body has healed enough to tolerate it. 

Why Elimination Diets Work

An elimination diet helps in treatment for a few possible reasons:

  1. It can help you find what specific foods you may have sensitivities to that cause an immune system response [7 Trusted SourcePubMedGo to source, 8 Trusted SourcePubMedGo to source].
  2. We do not always react to foods because of an immune response, but sometimes because the foods do not react well with our microbiome (the bacteria and other microbes that live in your digestive system and create a stable ecosystem), which an elimination diet can also help discover [4 Trusted SourcePubMedGo to source, 9 Trusted SourcePubMedGo to source].
  3. It can help indicate if you have a lack of digestive enzymes. This is when our body does not produce the enzymes needed to break down certain sugars or proteins like in the case of lactose intolerance. Removing foods your body can not digest can improve symptoms [10 Trusted SourcePubMedGo to source].

An elimination diet allows the gut and body to relax and reduces pressure on the digestive system by removing any foods that potentially drive inflammation. This rest and reset then creates a clean slate for reintroducing foods to see what foods work for you. 

Why Elimination Diets Are Better Than Food Sensitivity Tests

When you’re trying to figure out which kinds of foods trigger your symptoms and which ones you can tolerate, it might be tempting to invest in a food sensitivity test. These blood tests are widely used in functional and integrative medicine, and they differ from traditional allergy tests in that they look to identify more subtle intolerances or sensitivities rather than true allergies. They check for different antibodies produced by the immune system as a response to an allergen. 

But as it turns out, the information provided by food sensitivity tests may not actually be very useful or accurate. And research shows that elimination diets can be a lot more helpful (not to mention cheaper and more accessible) [2 Trusted SourcePubMedGo to source]. 

For example:

  • Blood tests for IgE antibodies show less than 50% accuracy [2 Trusted SourcePubMedGo to source].
  • The popular blood test kits you can get at home test only for certain kinds of antibodies known as IgG antibodies, but many food sensitivities are not due to this IgG response. 
  • In one review of studies looking at various forms of tests, from blood tests to hair samples, it was found that rather than any of these tests, “The most helpful diagnostic test for food intolerance is food exclusion to achieve symptom improvement followed by gradual food reintroduction” [1 Trusted SourcePubMedGo to source].
Elimination diet: woman holding a glass of milk

Which Conditions Can an Elimination Diet Help?

An elimination diet can help with a variety of health issues. Let’s look at three common conditions that have the most research behind them:

IBS

For people with irritable bowel syndrome (IBS), elimination diets have been particularly helpful. Specifically, the most compelling research has been with the use of a low-FODMAP diet as an elimination diet.

Two meta-analyses (the highest quality of research information) show that the diet reduced overall digestive symptoms and abdominal pain, and increased quality of life [11 Trusted SourcePubMedGo to source, 12 Trusted SourcePubMedGo to source]. Multiple studies have also found that a low-FODMAP diet improves symptoms of IBS, IBD, and other conditions [13 Trusted SourcePubMedGo to source, 14 Trusted SourcePubMedGo to source, 15 Trusted SourcePubMedGo to source].

Autoimmune Diseases

Autoimmune diseases have shown improvement with elimination diets [16 Trusted SourcePubMedGo to source, 17 Trusted SourcePubMedGo to source]. In fact, tests of c-reactive protein (this protein level increases as inflammation increases) show that an elimination diet lowers systemic inflammation [18 Trusted SourcePubMedGo to source].

Food Intolerances

Food intolerances, which is when your body is unable to break down parts of a food, improve on an elimination diet [1 Trusted SourcePubMedGo to source]. The most common intolerances are lactose, histamine, fructose, and FODMAPs (types of carbohydrates that are resistant to digestion in some people). 

The inability to digest these foods or the fermentation of these foods (such as in the case of FODMAPS) is what often causes digestive and non-digestive issues such as skin rashes, headaches, joint pain, and brain fog.

Elimination diets have also been shown to be helpful for other conditions and symptoms. For example:

How to Follow an Elimination Diet 

Starting an elimination diet can be challenging, especially if it’s one that cuts out a large number of foods, such as a low-FODMAP diet or the autoimmune Paleo (AIP) diet (which we’ll cover in more detail later). But, by following the right steps, you should be able to find the optimal amount of symptom relief with the least amount of restriction. 

Before starting an elimination diet meal plan, make sure you’ve cut out or significantly reduced your intake of objectively unhealthy foods (such as processed foods) and that your diet consists primarily of whole, fresh foods. 

It’s always best to remove additives, added sugar, processed or trans fats and oils, soy, artificial sweeteners, dyes, and processed carbs, grains, and proteins. 

Instead of processed foods, eat whole, real foods, such as vegetables, fruits, grains, nuts and seeds, spices, herbs, healthy fats (olive oil and coconut oil), and organic or free-range meat, poultry, and fish. 

Once your foundation has been established, you can begin your elimination diet. 

Which Diet Should You Follow?  

Elimination diet: Most Restrictive Diet infographic from Dr. Ruscio

There are many different types of elimination diets, from a moderate Paleo diet to a more restrictive low FODMAP diet. As a general rule, it’s best to start with the least restrictive diet, moving on to a more specialized protocol only if your symptoms don’t improve enough

Based on this principle, a good starting point is generally to follow a Paleo diet framework. In addition to processed and refined foods, this diet removes foods such as grains, legumes, and dairy products, which commonly cause immune reactions. 

In just a few weeks, a Paleo diet can help decrease inflammation by removing foods that cause an immune response [7 Trusted SourcePubMedGo to source, 8 Trusted SourcePubMedGo to source]. Many of my patients see significant improvements with the use of this diet. 

For others, the low-FODMAP diet is the best option. With this diet, you remove fermentable oligosaccharides, disaccharides, monosaccharides, and polyols, which are certain carbohydrates that are fermented by gut bacteria.

For those with bacterial overgrowths like SIBO, feeding gut bacteria with high FODMAP foods can be problematic, leading to symptoms like bloating, gas, and diarrhea. Some common FODMAPS are high fructose fruits like apples and pears, as well as broccoli, brussels sprouts, beans, wheat, and onions. 

As mentioned earlier, the low-FODMAP diet is especially helpful for IBS [24 Trusted SourcePubMedGo to source]. In fact, the British Society of Gastroenterology guidelines for the management of IBS suggests the low-FODMAP diet as a first line of treatment [25 Trusted SourcePubMedGo to source].

An elimination diet of any kind should follow three general phases, which we’ll outline below

  1. Elimination phase
  2. Reintroduction phase 
  3. Maintenance phase 

Elimination Phase

An elimination phase should last 2-3 weeks. During this time, follow your diet as closely as possible in order to best assess your body’s response. It’s a good idea to track your symptoms during this and the next phase of your diet. Keeping your meal plan simple with repeatable meals can relieve a lot of the stress of starting a new diet. 

Once you’ve been on a diet for 2-3 weeks, you can follow this guide to determine where to go next. 

  • If your symptoms improved significantly, you can move on to the reintroduction phase. 
  • If your symptoms improved somewhat, you may want to try a more restrictive version of the diet you were following for a couple of weeks, looking out for additional improvements. 
  • If your symptoms did not improve, you might want to move on to a different kind of diet. This may be a low FODMAP or a low histamine diet, depending on your symptoms and what you think may be causing them. There may also be an underlying gut issue that needs to be resolved. 

Don’t spend too much time on any one diet. Try it for a short period of time, about two to three weeks, and move on if you aren’t seeing positive improvements. 

Elimination diet: woman holding an apple and a pear

Reintroduction Phase

Ideally, we want a diet that is as diverse in whole foods as possible, and we are not meant to be on a strict elimination diet forever. Reintroducing eliminated foods creates a personalized diet for you to support your health. When reintroducing foods, I recommend starting with the food you miss the most first. 

When noting any recurrence of symptoms, you may find that a food is one you can’t eat at all or you have a certain tolerance level for it. For example, some people can have one tablespoon of cream in their coffee and not experience symptoms but have stomach distress with a few ounces of cheese. 

The process for reintroducing foods is as follows:

  • Reintroduce only one new food at a time over about three days. On the first day, have a small amount and look for any symptoms in the next 24 hours. If you have no symptoms, increase the amount of the reintroduced food to check for your tolerance level. 
  • If you can, reintroduce foods from the same food group. For example, if you are reintroducing black beans, next try introducing lentils rather than then trying cheese which is a different group of food. 

It’s normal to have some ups and downs in the reintroduction phase. With some foods, you may notice a big reaction so you know it is a trigger, and others might cause a normal amount of bloating during digestion. If you are unsure if a food is causing a symptom, then take a few more days for your reintroduction to see if digestion evens out. 

Going through the reintroduction process will allow you to create a customized diet that works for you and removes problem foods from your diet. 

Making a food diary spreadsheet of your common symptoms and quickly checking off days when you have the symptoms can be helpful here. The most common digestive symptoms are constipation or diarrhea, bloating, gas, and reflux. 

Remember to note non-digestive symptoms as well such as rashes, hives, joint pain, brain fog, fatigue, inability to focus, and headaches.

Maintenance Phase

After you have found what foods you can tolerate, that is the diet you will use to maintain symptom relief. If part of your symptoms are due to leaky gut or another condition that the elimination diet may improve, a few months into the maintenance phase you may be able to try reintroducing some of the foods that you found you can not eat. 

Over time you are looking to create the most diverse and nutrient-dense diet possible without a recurrence of symptoms. 

Grilled vegetables and steak

Be Responsible With Your Elimination Diet

Elimination diets are amazing treatment tools, but it’s important to use them as intended (for the short term). Figuring out how to heal chronic illness is an individualized practice, and while you may end up eliminating certain trigger foods for most of your life, needing to stay on an extremely restrictive diet forever should not be a common occurrence. 

If you are still having trouble after trying a more restrictive elimination diet and reintroduction, you may want to reach out to a functional medicine practitioner to help support your wellness. There may be other contributing factors, such as some bad gut bugs, that need to be resolved. If you would like to work with us, please reach out to our clinic.

It’s helpful to know that normal digestion does sometimes include a bit of bloating or gas, so don’t be alarmed and worried if a food causes slight symptoms. These issues may go away with a longer reintroduction period. 

I also want to quickly mention the placebo/nocebo effect in elimination diets. Placebo has gotten a bad reputation as meaning “fake,” but it’s not a made-up reaction. It’s a natural and helpful response to an intervention. Knowing you’re getting help may reduce stress and anxiety and improve digestion [26 Trusted SourcePubMedGo to source, 27 Trusted SourcePubMedGo to source]. 

There is also the nocebo effect, which is when we expect harm from an intervention. It’s understandable that maybe reintroducing a food that you’ve previously associated with symptoms is stressful and scary for the brain, and this might contribute to some stomach distress or fatigue. 

These placebo and nocebo effects are also one reason why food intervention trials often have varying results in terms of effectiveness. Even a less than welcoming health care professional working with clients to implement diet changes can affect results.

Again, a longer reintroduction period of certain foods and looking into some mindfulness practices that help in improving gastrointestinal symptoms may be helpful here. 

Woman happily preparing her food

Trust the Process

Overall, trust in the process and know that elimination diets are a great tool in your wellness toolbox that can help you customize your ideal diet plan. Take time in the reintroduction phase, and trust that you will find what works for you. 

When in doubt, you can always get help. In fact, we have two additional resources for you. If you want to go more in-depth with gut healing and learn more about elimination diets, you can read more in my book, Healthy Gut, Healthy You, and, of course, our clinic is always ready to welcome you as a new patient.

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