An elimination diet, broadly speaking, is a specialized eating plan that attempts to identify trigger foods for people with food sensitivities. It’s a short-term diet, not a long-term lifestyle change, and it’s useful when establishing a diagnosis for various autoimmune, neurodevelopmental, or gastrointestinal (GI) disorders.
For example, to determine whether a person has a sensitivity to gluten (a common protein), doctors may recommend a restriction diet that doesn’t include gluten, but the person may be allowed to consume dairy and other possibly problematic foods. If a person has a different food sensitivity, the diet plan might eliminate dairy, eggs, gluten, and other potential triggers, then add those foods back gradually to determine the source of the symptoms.
We should note that there’s a significant difference between a food allergy and food intolerance (also known as a food sensitivity). When a person has a food allergy, their immune system reacts dramatically when presented with a trigger. That can cause serious or even life-threatening symptoms. Food intolerances are generally less severe and often cause gastrointestinal symptoms such as bloating or flatulence.
Elimination diets are typically used to identify food intolerances, not food allergies, but they’re recommended for a wide variety of potential conditions, including some disorders that may seem to have nothing to do with diet. Your physician might recommend an elimination diet as a treatment for ADD/ADHD, migraines, narcolepsy, skin conditions, or even asthma.
Recent health trends have helped the concept of elimination diets go mainstream, and some websites provide resources for people who want to attempt restricted diets on their own. That can be a dangerous idea. If you rush into a restricted eating plan without proper preparation, you could make serious mistakes that could endanger your health.
If you’re considering an elimination diet, or if a healthcare provider has recommended this type of eating plan, here’s what you need to know.
Who should consider an elimination diet?
Before making any significant changes to your diet, you should speak with a physician or dietitian. That’s especially important if you’re contemplating an eating plan with severe restrictions.
“There are steps to take with an elimination diet,” says Deborah Malkoff-Cohen, a registered dietitian, certified diabetes educator, and the founder of City Kids Nutrition in New York. “First, you have to meet with someone who’s qualified.”
That’s especially crucial if you already have dietary restrictions, if you’re nursing or pregnant, or if you have any health conditions that could affect nutrient absorption. One potential issue: You might not be aware of those nutritional deficiencies.
“For instance, my friend who’s nursing her baby—let’s say that she cuts out dairy,” Malkoff-Cohen says. “If she doesn’t take in enough calcium, the baby will take that from her bones, and she’s going to be at risk for osteoporosis.”
“Depending on your diet, supplements or different food choices might be essential,” she says. “You want to make sure that you’re eliminating the right things and that you’re reintroducing foods in the right way.”
Part of the reason that medical supervision is so important is that there are a wide variety of elimination diet protocols, some of which are better suited than others for certain conditions. Your physician may want to restrict entire food groups, foods that were processed in a certain way, or foods with specific additives. That’s part of the reason that you shouldn’t try to take on an elimination diet on your own—you’ll need a highly personalized diet plan.
“[The diet] really depends on the age group and the symptoms,” Malkoff-Cohen says. “I think a lot of people think it’s trendy to be on an elimination diet, somehow. You’re gluten free, or carb free, or dairy free. Everyone’s free of something—but that’s not necessarily healthy. You aren’t necessarily doing your body a service. And you can’t take everything out [of your diet].”
Understanding the Phases of an Elimination Diet
A typical elimination diet consists of several phases. After meeting with a specialist, patients will usually begin with a severely restricted diet consisting of basic, easy-to-digest foods; this is known as the elimination phase.
“You can’t always take everything out,” Malkoff-Cohen says. “We’ll often do a bland diet with protein and vegetables. We’ll take out gluten, dairy, soy, nuts, and eggs. Then we’ll add [food types] in one by one over several weeks and see what comes back. Then, you can figure out the culprit.”
That’s known as the reintroduction phase of the elimination diet. It’s extremely important to introduce a single type of food at a time.
“You have to have the patient feel better first before reintroducing foods. You have to get them back to baseline,” she says. “You have to get all of the symptoms to go away before you can have them reappear.”
Patients often make two types of mistakes: They don’t fully eliminate potential triggers or they add trigger foods into their diets too quickly.
“You have to eliminate the food from every part of your diet. You have to avoid trace amounts—you have to do it 100 percent,” Malkoff-Cohen says. “For instance, if you have something like celiac disease, when you test positive, you have to go through all of your products, including things like hair products and cosmetics.”
“As strange as it sounds, some cosmetics have gluten. It’s also used as a thickening agent in a lot of medications. It’s in hot dogs—most people wouldn’t consider that. So you have to have professional oversight. “
Patients also have to be careful when they’re not preparing their own meals. Restaurants might use dairy when making their bread, for instance, throwing off the diet and triggering a reaction that invalidates valuable diagnostic information. If you’re on an elimination diet, you’ll need to avoid making assumptions about your food, even if they seem reasonable.
As you’re changing your diet, you’ll also need to take extra care to monitor your nutritional intake. Your dietitian may recommend specific foods or nutrient supplements to help you avoid deficiencies. Don’t assume that your diet is becoming healthier simply because you’re cutting out triggers.
“Let’s say someone decides that gluten and dairy are culprits. You have to make sure you’re getting enough calcium and that the grains you’re choosing are the healthy ones,” Malkoff-Cohen says.
“‘Gluten-free’ is not healthier, unless you have a sensitivity,” she explains. “Unless you pick the higher fiber, more nutritious gluten-free grains, you aren’t necessarily doing your body a favor.”
How long does an elimination diet last?
Depending on the goal of your diet, you may have a restricted diet for several months. The most severe phase of the diet typically lasts about three weeks. You should carefully track symptoms and keep a food log, as you won’t be able to reintroduce foods until you’ve eliminated the triggers.
“Some people may see a change in their symptoms in only a few days,” Malkoff-Cohen says. “If you’re addressing gastrointestinal issues, some symptoms might go away as soon as you take the food out [of your diet] … but you also have to heal the gut, which might take a few days to really feel a difference. But you won’t have stomach cramping and things like that.”
“With eczema, skin conditions, and non-GI diseases, the changes could take a few weeks. It’s highly personalized to the patient,” she adds.
Keep track of physical, mental, and emotional symptoms. Doctors often watch for things like mood swings or “brain fog,” a feeling of fatigue that can accompany certain food sensitivities (including gluten intolerance). As some symptoms can be severe, you’ll want to reintroduce potential trigger foods carefully.
“If you take dairy out for a few weeks, I don’t want you just eating cheesecake right afterwards,” Malkoff-Cohen explains.
Elimination diets are, by nature, highly personalized, but the reintroduction phase should always be handled carefully. If your physician believes you have a food allergy, you should only reintroduce foods under medical supervision; allergens can cause a potentially life-threatening reaction called anaphylaxis, which has a rapid onset. Even a trace amount of an allergen might prompt a serious reaction, so it’s important to take the reintroduction phase seriously.
What are the benefits and limitations of elimination diets?
To be clear, elimination diets are never intended for weight loss; they’re highly specialized diets that are meant to identify triggers. They’re also limited in terms of their capabilities. To determine whether a person has celiac disease, for instance, doctors may need to perform an endoscopy and blood tests.
“If you take gluten out [of your diet] before those tests, your results might not be accurate,” Malkoff-Cohen explains.
By the same token, you don’t need to attempt an elimination diet if you have obvious evidence of a trigger.
“For instance, my friend’s son reacts to gluten,” Malkoff-Cohen says. “She was asking about elimination diets. I said, ‘Why would you need confirmation that he’s sensitive to gluten?’ If every time he eats it, he throws up, he shouldn’t be eating it. You don’t always need a confirmation. If every time you eat shrimp, you react, don’t eat shrimp.”
If you’re regularly experiencing mild symptoms, consider keeping a food journal while eating your normal diet.
“Journaling can be very helpful,” Malkoff-Cohen says. “If, for instance, you have migraines, you can go back and check what you’d eaten before your last migraine or aura, then try taking those foods out. You don’t necessarily need the full elimination diet in every case.”
Elimination Diets for Children: What to Know
Physicians may recommend elimination diets for children, which can create quite a bit of stress for both kids and parents. Most kids already have fairly restricted diets—even if that means that they refuse to eat broccoli—and many parents are apprehensive about applying severe restrictions.
“I see a lot of kids [with] autism, and they’ll do gluten- [or] dairy-free diets. That type of diet can sometimes help kids with autism by limiting some of the primary symptoms in terms of concentration, eye contact, and things like that,” Malkoff-Cohen says. “Sometimes it works, sometimes it doesn’t. When you have a kid who eats five foods, you have to consider that going free from gluten or dairy could mean eliminating their whole diet.”
Elimination diets aren’t exactly fun for adult patients. But for kids, they can be downright torturous, and they’re not an option when a child already has a severely restricted diet. With that said, if your doctor has recommended an elimination diet, there are ways to make the process easier for your child.
“When you work with children, you want to replace what they’re already eating,” Malkoff-Cohen says. “If a child like waffles, you replace it with a gluten-free waffle. If they like pizza, you try a gluten-free pizza. Find analogs that the child will be more likely to accept.”
Granted, it’s not exactly a foolproof strategy. Parents should try to understand the child’s emotional state when starting out on a highly restricted diet.
“Kids are picky, and they’re not always going to like the replacement,” she says. “A 5-year-old doesn’t understand what’s happening…and gluten-free pizza doesn’t usually taste like a normal pizza.”
Try planning all meals carefully at the outset of every week, then commit to eating the same foods as your child. Many hospitals offer online resources to make this process easier, although it’s important to follow the exact recommendations of a dietitian, even if they conflict with the information found in online resources.
As with adults, journaling is an essential part of the process. Parents should work with kids to log both physical and emotional symptoms, along with food types, quantity, and meal times.
And while we don’t want to belabor the point, it’s imperative that parents obtain medical supervision when implementing significant changes to a child’s diet. Never attempt an elimination diet under any circumstances without help from a physician or dietitian.
That really goes for all age groups. Elimination diets are diagnostically useful, and although they can restore quality of life to patients with food sensitivities, they’re not something to take lightly.