How to do an elimination diet
An elimination diet can be a useful tool for controlling uncomfortable symptoms of gastrointestinal disorders such as irritable bowel syndrome (IBS) and gastroesophageal reflux disease (GERD). Often the symptoms can be intense, painful, and even confusing if you’re not sure what’s triggering them.
First things first: you should not attempt an elimination diet without consulting your doctor, who may refer you to a nutritionist to assist you through the process. There is a risk of developing nutritional deficiencies with any major dietary change, and it’s important to ensure you’re following the diet effectively for best results. Many foods contain ingredients you wouldn’t necessarily expect, which could derail your elimination diet. Therefore, keeping a food journal and working with a nutritionist can make this process easier.
Learn more about gut health and how to improve your digestion here at Live Science.
What is an elimination diet?
There are several reasons someone might try an elimination diet. If you have troubling gastrointestinal symptoms, you may want to exclude certain foods to identify the source of your problems.
Common elimination diets are the low-FODMAP diet or the six-food elimination diet, which are usually carried out over several weeks or months. The Journal of Gastroenterology and Hepatology (opens in new tab)recommends not exceeding six weeks in the elimination phase, especially on a low-FODMAP (fermentable oligo-, di-, monosaccharides and polyols) diet, as this can negatively impact your gut microbiome.
“An elimination diet is a method of identifying foods that a person is intolerant or sensitive to,” explains Rachel Clarkson, Doctify (opens in new tab)-rated dietitian and nutritionist and founder of The DNA Dietitian (opens in new tab). “A person can start an elimination diet to identify the problem foods in their diet that are causing symptoms.
Rachel Clarkson, RD, MSc, PGDIP, BSc
Rachel Clarkson is an HCPC Registered Specialty Dietitian and Nutritionist. She was educated at King’s College London in the UK and completed further clinical training at Royal Marsden, St Thomas’s Hospital and Imperial College Trust. She recently published her epigenetic research from King’s College London in a peer-reviewed medical journal and continues her professional development with courses on topics such as the low-FODMAP diet for IBS management.
“The duration of an elimination diet can vary depending on the type and number of foods that are eliminated and then reintroduced or challenged. One of the most commonly used and scientifically backed elimination diets is the low-FODMAP diet. This diet excludes foods that contain compounds called FODMAPS, which cause digestive symptoms in people with IBS. This elimination diet can take anywhere from 10 to 16 weeks for all three phases: elimination, reintroduction, and personalization.”
Foods high in FODMAP include some vegetables such as onions and garlic, some fruits (especially stone fruits), beans and lentils.
“Reviewing trigger foods or ingredients that may make symptoms worse is helpful, so keeping a food and symptom diary can be a worthwhile approach,” adds Kim Plaza, nutritionist at Bio-Kult.
How to follow an elimination diet
If you suspect you have a specific trigger food (like dairy or gluten), you should skip it for a few weeks to see if your symptoms improve. However, if you are unsure what your trigger foods might be, or have been diagnosed with a specific condition that might benefit from a broad-spectrum elimination diet, you should follow the steps below with the guidance of a healthcare practitioner.
elimination
“This phase typically lasts 2-6 weeks, during which all potentially problematic foods are eliminated from the diet,” explains Clarkson. “By the end of this phase, the symptoms should have completely disappeared.”
A nutrients (opens in new tab) Journal reviews show that the low-FODMAP diet in particular significantly reduced bloating and pain in the subjects. A clinical study reported in the Journal of Allergy and Clinical Immunology (opens in new tab) also found that an elimination diet achieved remission in 43% of study participants with eosinophilic esophagitis regardless of age.
reintroduction
In the reintroduction phase, all eliminated food groups are systematically tested.
“This phase can last anywhere from 4 to 8 weeks, depending on the number of foods that are in question,” says Clarkson. “During this phase, individuals should continue to eliminate all problem foods and add the foods that are being challenged to determine if they are causing the problem symptoms. Each potentially problematic food is challenged individually and the amount is gradually increased to understand if the person is intolerant to that food and at what level symptoms appear.”
Integration/Personalization
The final phase of an elimination diet involves reviewing and discussing the results of the nutritional challenges, Clarkson says.
“Also, other challenges may be mandated where more than one problematic food is introduced at a time. Finally, the use of supplements, digestive enzymes, or probiotics can be discussed.”
What can you eat on an elimination diet?
It is advisable to prepare your meals at this point using raw ingredients so that you know exactly what you are eating. Processed foods often contain flavorings such as onion or garlic powder, which can trigger symptoms even in small amounts.
- Unprocessed meat and fish (no shellfish)
- Rice based foods
- Non-dairy fats such as vegetable oils
- Low-FODMAP fruits and vegetables
What not to eat on an elimination diet?
The most common dietary triggers are often the first to be eliminated in order to test symptom response:
- dairy
- wheat and rye
- Nightshade vegetables (such as potatoes, tomatoes, and peppers)
- shellfish
- nuts and seeds
- Leeks (onions and garlic are high in FODMAPs and cause irritation in many people)
- legumes
- Citrus fruits (these may be triggers for people with acid reflux and GERD)
Plaza also says highly processed foods can be problematic. “Processed foods, which are high in hidden sugars, sweeteners, additives, and emulsifiers, are likely to have a negative impact on the bacteria that live in the gut — leading to increased inflammation and worsening IBS symptoms,” she says. “Many people notice a rapid improvement in their digestion simply by cutting out processed foods and switching to homemade whole foods instead.”
What Are the Benefits of an Elimination Diet?
According to Clarkson, Identifying your trigger foods can help you make the best choices for your body. “The main benefit of an elimination diet is identifying the foods that cause symptoms and the amount of those foods that cause symptoms,” she says. “This is a huge benefit because it allows you to make the best choices for your body and helps you understand your body on a deeper level.”
Are there any risks with an elimination diet?
With an elimination diet, you must ensure that you are still getting your recommended daily amount of each nutrient, and as such you should do this under professional supervision.
“There can be risks in eliminating food groups for an extended period of time,” says Clarkson. “Working with healthcare professionals can ensure you’re following the elimination diet correctly and in the safest way.”
This article is for informational purposes only and is not intended to provide medical advice.