10 Things to Know Before Trying an Elimination Diet

While 19% of adults claimed to have a food allergy, a recent survey published in JAMA Network Open found only about 11% of adults actually have one. So, before you cut entire food groups from your diet, it’s best to methodically identify which food or foods may be causing gastrointestinal problems, headaches or chronic pain. This is where an elimination diet, which systematically and strategically eliminates certain foods or ingredients from one’s diet, may be useful.

Here, 10 things to know before trying one:

“An elimination diet can deliver answers for someone who has likely struggled with the frustration of not knowing what’s been causing their uncomfortable symptoms for so long,” says Cara Harbstreet, RD, of Street Smart Nutrition. Many experts, such as gut health specialist Nour Zibdeh, RD, use tests as well as your health history to help you decide where to start.

Some elimination diets focus on one food group such as dairy or nightshades (e.g., tomatoes, bell peppers, eggplant), while others might focus on removing fermentable sugars, such as a low FODMAP diet. Because they are meant to be highly individualized, you can pick an elimination diet that works for you.

While weight loss might occur during an elimination diet, the goal is really to learn what foods cause certain sensitivities (see #1).

“Although I always advocate that you and you alone are the best expert of your body, working with an experienced dietitian can be immensely helpful for avoiding unnecessary restriction,” Harbstreet says. They can help ensure you are getting the nutrients you need while on the diet and also help you find solutions to your symptoms.

To be successful with an elimination diet, you need to plan in advance, Zibdeh says. “Most of the time, it’s not going to be easy to grab a meal or snack on-the-go. Pack foods ahead of time and choose restaurants or grocery stores where you know you can find options that comply with your diet when traveling,” she says.

Many elimination diets call for removing entire foods or food groups — the biggest culprits tend to be milk, eggs, peanuts, tree nuts, fish, shellfish, soy and wheat — for about 4 weeks. Then you reintroduce a food or food group, one at a time, and notice how your body reacts. “It can be a long and frustrating process, because it can take time for patterns to emerge that give you the insight needed to definitively say whether you’ve found an allergy or sensitivity,” notes Harbstreet.

If you decide to try an elimination diet, there are no cheat days. “Food sensitivities are immune reactions, and a food’s effect can last up to three days,” Zibdeh explains. If you only follow the plan half the time, you may not get any relief or see any improvement.

As you reintroduce foods, keeping track of not only what you eat but also all of your symptoms in detail — What time of day did they happen? How severe were they? What else was going on that could have triggered the symptoms, such as lack of sleep? — is a great way to help you get the most out of an elimination diet.

In some cases, “elimination diets have the potential to damage one’s relationship with food or promote disordered eating behaviors [such as orthorexia]. In the absence of a food allergy or sensitivity, it can promote fear or distrust around foods or increase anxiety around certain foods,” says Harbstreet. Be sure to work with a registered dietitian and, if you find yourself preoccupied with thoughts about food, talk to your RD or find an eating disorder specialist on the National Eating Disorders Association site.

“An elimination diet is meant to be a trial to get clues about your body,” Zibdeh says. The goal is to understand why you can’t tolerate certain foods and then figure out what changes you need to make to ideally be able to eat those foods symptom-free. While staying on an elimination diet long-term is sometimes necessary, such as in the case of celiac disease, for most, doing so may put you at risk of nutrient deficiencies.

Trying an elimination diet can be helpful if you do so under the guidance of a registered dietitian who supports a plan with the right mindset. However, “if you’re considering an elimination diet for trendy or image-focused reasons, consider whether the risks are worth it and what your motivation is for wanting to cut out certain foods,” says Harbstreet.