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What is an elimination diet?

An elimination diet is a process used to identify food intolerances, sensitivities, and allergies. Those following an elimination diet temporarily remove one or more specific foods from their diet. The restricted food(s) are then gradually reintroduced one at a time in a systematic manner, while monitoring the individual’s response to each food. The idea is that at the end of the reintroduction period, the individual will know which foods they did and did not tolerate. Based on this information, they will continue to avoid the foods they did not tolerate and add back the foods they did tolerate.

If using an elimination diet to identify food allergies, an individual will partake in oral food challenges under medical supervision to assess for potential allergic reactions. While there are specific blood tests and skin prick tests that can be ordered by a physician to identify food allergies, these may yield false positive results 50-60% of the time, according to the Food Allergy Research & Education (FARE) organization. Additionally, there currently is no evidence-based, clinically validated test to identify most types of food intolerances (with a few specific exceptions such as lactose and sucrose intolerances). For these reasons, an elimination diet is considered the gold standard for identifying food intolerances, sensitivities, and allergies.

Who should follow an elimination diet?

You may be a good candidate for an elimination diet if you experience frequent symptoms such as abdominal cramping, gas, bloating, diarrhea or constipation, headache, or nausea and have already been evaluated by a physician to rule out potential underlying medical causes that require treatment. Additionally, if you have been diagnosed with certain medical conditions that are strongly influenced by diet, your doctor might recommend a specific type of elimination diet as part of your treatment plan. For example, those with eosinophilic esophagitis (EoE), an immune condition affecting the esophagus, are often advised to try a specific type of elimination diet to help determine which foods exacerbate the condition. Similarly, those with irritable bowel syndrome (IBS), a function disorder of gut-brain interaction, may be advised to try a low FODMAP elimination diet to determine their dietary triggers. Other conditions such as eczema and migraine headaches can be associated with food sensitivities, therefore individuals with these conditions may also try an elimination diet to see if they notice improvements. Lastly, if after consuming certain foods or beverages, you frequently experience unpleasant symptoms, you might consider eliminating these foods or beverages for a few weeks and then gradually reintroducing them one at a time to confirm or rule out an intolerance or sensitivity. If you suspect you have a food allergy, however, this process should only be done under medical supervision. Some additional examples of elimination diets include but are not limited to the elimination of:

• Lactose
• Fructose
• Sucrose
• Histamines
• Dairy
• Gluten
• Wheat
• Eggs
• Soy
• Corn
• Peanuts and/or tree nuts
• Fish and/or shellfish
• Red meat
• Sulfites, MSG, or other food additives
• Caffeine
• Alcohol

You can use the Fig app to help you start and track your elimination diet.

How to begin an elimination diet

Before beginning an elimination diet, it’s important to seek guidance from a medical professional such as a physician or registered dietitian. Elimination diets and food reintroductions are not only difficult to follow and interpret on your own, but physicians and registered dietitians are also able to identify red flag symptoms that may indicate a need for diagnostic testing to rule out medical conditions that require intervention. Additionally, it may not be safe or appropriate for certain populations to follow an elimination diet, and eliminating multiple foods from your diet can lead to nutrient deficiencies. A physician or registered dietitian can recommend an appropriate form of elimination diet for your specific concerns, and registered dietitians are trained to help you structure your diet so that you still obtain the nutrients you need.

Once you begin your elimination protocol, it is generally best to follow the elimination phase for  2-6 weeks, to see if you notice improvements in how you feel. If you do not notice symptom improvement, then the foods you eliminated were likely not the culprit of your symptoms and you should seek guidance from your healthcare team to be reevaluated. If you do notice improvements, you can then begin to reintroduce one food you eliminated. It’s best to start “slow and low,” by testing a small portion size, gradually increasing the portion size over the course of 3 days. For example, try a small portion of the test food on day 1 and if all goes well, try increasing the portion size on day 2. If you continue to feel well, try a slightly larger portion size on day 3. Your day 3 portion size should be representative of the portion size you would typically consume, or slightly larger than your typical portion size for this food. If at any point you notice your symptoms worsen, it is likely that you do not tolerate that food. Before moving on to the next test food, allow at least 2-3 days of a “washout” period, where you go back to the full elimination diet. If you still experience symptoms past 2-3 days, then continue to follow the elimination diet until you feel back to baseline. Then, you can try testing your next food using the same protocol. Once you are finished with all of your food tests, you can gradually reincorporate the foods you tolerated back into your diet, and continue to avoid the foods you did not tolerate.

Helpful tips when starting an elimination diet

Identify resources to help you through the process

Many elimination diets are nuanced and determining which foods are compliant can be confusing. Looking up online resources and joining support groups on social media platforms can help you through this process. Additionally, using the Fig app makes identifying suitable foods and beverages a breeze! You can plug in your restrictions and then scan items at the grocery store to see if they likely match your needs.

Consider timing

Before beginning an elimination diet, it’s important to consider when is the best time to begin. If you are going on a long vacation soon or have a few holiday meals coming up, perhaps it would be easier to begin once you are back to your usual routine. If there is a medical urgency to begin your elimination protocol right away, however, this is not an option.

Keep a food and symptom journal

It’s important to keep a food and symptom journal throughout the entire process to help you keep track of your symptoms and identify patterns. Noting your sleep quality and duration, physical activity, and stress level may also help you tease apart whether or not symptoms are attributed to food reintroductions or other factors. If you notice your symptoms worsened on a day when your stress level was high and you slept poorly the night before, your symptoms may not necessarily be tied to the food you ate, but rather influenced by outside variables.

Plan ahead

Looking up suitable recipes, planning out your meals ahead of time, and making a grocery shopping list will make sticking to your elimination diet easier and more enjoyable. If you are able to set aside some time each week for meal preparation, you may also find that putting together your meals and snacks is less onerous and more time efficient. This can be as simple as pre-chopping vegetables you plan to cook later or making extra of the protein you are cooking for dinner one night, so that you get a few meals out of the cooking effort. If you go to the trouble of making a more elaborate dish, try doubling or tripling the recipe, then portioning out leftovers into airtight containers, and freezing them so you have easy meals already prepared on days when you don’t have the time or energy to cook – just reheat and eat! You can also look through restaurant menus and make a list of takeout options suitable for your elimination diet for times when you are eating out or could use a break from cooking.

Only reintroduce foods when you feel at baseline

It is critical that you only reintroduce foods when you are feeling well at baseline and are in your usual routine, to prevent outside variables from impacting food reintroduction responses. Reintroducing a food on a day when you are experiencing symptoms, tested out a new supplement or medication, have not slept well, are in a new environment, or are very stressed, can all impact your symptoms. You may attribute your symptoms to the specific food you reintroduced and unnecessarily avoid it when in fact, you may tolerate the food very well under normal circumstances.

Consider working with a registered dietitian to guide you

Elimination diets can be tricky to navigate on your own, and working with a registered dietitian throughout the process can help guide you and interpret your reintroduction response. This is particularly important if you are following an elimination protocol as part of your treatment plan for a medical condition or food allergy identification.

Things to look out for on an elimination diet

Generally, elimination diets that restrict multiple foods should not be followed for more than 8 weeks. Following a very restricted diet for an extended period of time may lead to nutrient deficiencies, unintentional weight changes, and adverse shifts in the gut microbiome.

If you experience significant weight loss, worsened symptoms, or do not experience any improvements in your symptoms after eliminating foods, you should consult with your healthcare team and discontinue the elimination diet unless they advise otherwise.

Who is an elimination diet not for?

Depending on the individual, elimination diets may not be appropriate for young children, the elderly, malnourished individuals, those with a history of an eating disorder or disordered eating, and those who already follow a very restricted diet.

You should not follow an elimination diet if you experience a sudden onset of symptoms and have not been evaluated by a physician to rule out conditions that could require medical treatment. In these cases, starting an elimination diet may just delay diagnosis and treatment, possibly leading to complications.

Conclusion:

Elimination diets can be an effective way to identify your specific dietary triggers, however, they are not for everyone. Keeping a food and symptom journal, limiting exposure to confounding variables, planning ahead, seeking professional guidance when needed, and utilizing helpful resources like the Fig app, all help you to get the most out of your elimination diet.  

Photo by Farhad Ibrahimzade on Unsplash