What You Should Know Before Trying an Elimination Diet

If you’ve been feeling unwell and none of the treatments you’ve tried have worked, look to your diet. Systematically cutting items from your diet and seeing how you feel can be one way to see if food is making you feel crummy. And if so, which foods, says Heidi Turner, M.S., R.D.N., a medical nutrition therapist at The Seattle Arthritis Clinic.

Elimination diets are used to pinpoint the underlying cause of a wide range of health problems, from digestive issues and heartburn to joint paint, allergies, migraines, insomnia, anxiety, depression, and skin issues, she says.

“If you’re saying, ‘Oh my gosh, I have these hives every day and these medications and supplements aren’t working,’ then you want to be looking at the foods you’re eating,” says Turner. “Food has the ability to impact our immune system so significantly.”

Has a healthcare provider suggested you try an elimination diet, or did you Google your symptoms and now you’re wondering if you should try one yourself? Maybe your best friend keeps telling you how the Whole30 diet changed her life? This is what you should know before cleaning out your fridge.

What is an elimination diet?

Typically completed under the guidance of a registered dietitian or a primary care provider who specializes in integrative medicine, an elimination diet removes antigenic foods, which are those found to create an immune response in some people, says Turner. 

Wheat, dairy, gluten, eggs, soy, sugar, alcohol, caffeine, corn, citrus fruits and nightshade plants are typical culprits, she says. In people who are sensitive to them, gluten and dairy consumption may cause digestive issues or lead to mood issues, for example. And nightshades—tomatoes, eggplant, white potatoes, pepper, paprika and tobacco—may aggravate arthritis in some people, Turner says.

There is no one-size-fits-all approach to elimination diets, and they usually range anywhere from two to six weeks, followed by a reintroduction period, says Turner.

“At the end of that period what you’re trying to do is determine whether any of those foods are causing any symptoms in your body,” says Turner. “How do you feel once all of these foods have been eliminated?”

The popular Whole30 diet—which cuts out grains, dairy, legumes, alcohol and added sugars for 30 days—is a trendy version of elimination diets that dietitians and physicians have been recommending to their patients for years.

It’s an opportunity to learn about your diet

The goal of an elimination diet is to cut out foods long enough to calm the immune system so when you start adding foods back in, you’ll clearly notice a reaction, says Turner. Typically, two to three weeks is a good time frame for accomplishing this.

The goal is to aim for 100-percent compliance, but if you accidentally slip up or just can’t resist something for one meal, you should take note of how eating the contraband item makes you feel, she says. (This is not the case for Whole30, where strict rules require that you start over at day one with any slip-up.)

Because you’re cutting out lots of prepared foods and many of the things you’re used to cooking, an elimination diet can be an opportunity to think about food in a way you haven’t before, says Turner. 

Maybe you’ll learn that you actually love eating sweet potatoes for lunch—or that you don’t miss sugar in your morning coffee after all. These can be lessons that you take with you after the elimination diet is over, regardless of what you learn about food sensitivities, says Turner.

Reintroduction is the hardest part

You’d think abstaining from foods that are a regular part of your diet would be the hardest part. But reintroducing foods back into your diet can be tough, says Turner.

If something you’ve been eating has been causing your symptoms, you’ll probably feel pretty good when you stop eating it. 

Many people complain of headaches, digestive issues and skin problems during the reintroduction period, Turner says.

This is why the length of an elimination diet matters. It’s not just committing to the length of your diet—you also have to tack on additional days, or even weeks, after the diet to slowly reintroduce foods. 

For example, if you cut gluten and dairy from your diet for three weeks, you would introduce gluten for two days, then go back to the full elimination for two days while assessing how you feel. After that, you would add in just dairy for two days, then return to the diet for two more days. With just two items eliminated from your diet, the reintroduction period is already eight days long.

A three-week diet with several off-limits items will require a three to five week reintroduction period, says Turner.

To make things easier, plan accordingly (ideally not around holidays or vacations) and ask your family and friends for support.

“It can be really challenging to be restricting your diet in the household when everybody else is eating other things,” she says.