CNET logo Why You Can Trust CNET

Our wellness advice is expert-vetted. Our top picks are based on our editors’ independent research, analysis, and hands-on testing. If you buy through our links, we may get a commission. Reviews ethics statement

Stomach Problems? A Food Elimination Diet Could Help

An elimination diet is one way to figure out what's causing digestive issues and more. But it's important to do it properly.

Giselle Castro-Sloboda Fitness and Nutrition Writer
I'm a Fitness & Nutrition writer for CNET who enjoys reviewing the latest fitness gadgets, testing out activewear and sneakers, as well as debunking wellness myths. On my spare time I enjoy cooking new recipes, going for a scenic run, hitting the weight room, or binge-watching many TV shows at once. I am a former personal trainer and still enjoy learning and brushing up on my training knowledge from time to time. I've had my wellness and lifestyle content published in various online publications such as: Women's Health, Shape, Healthline, Popsugar and more.
Expertise Fitness and Wellness
Giselle Castro-Sloboda
Medically Reviewed
Reviewed by: Amelia Ti Medical Reviewer
Amelia Ti is a Registered Dietitian (RD) and Certified Diabetes Care and Education Specialist (CDCES) based in NYC. She completed her Bachelor's in Nutrition & Dietetics at NYU and Master's in Applied Nutrition at Russell Sage College. Amelia's evidence-based knowledge and passion for the field allow her to translate nutrition research and innovation to the public.
Expertise Nutrition | Dietetics | Diabetes Care | Nutrition Innovation Credentials
  • Registered Dietitian
  • Certified Diabetes Care and Education Specialist
  • New York University, BS in Nutrition & Dietetics
  • Russell Sage College, MS in Applied Nutrition
7 min read
Person holding their stomach and a handful of wheat.
Getty Images/Andrey Popov

If you break out into rashes or experience stomach discomfort and you're not sure which food is causing it, you may have considered a food elimination diet. A food elimination diet is a way to find out which foods could be causing a sensitivity, intolerance or possible allergies. Even though there are many popular elimination diets out there, it's important to receive proper guidance from a professional like a registered dietitian and a gastroenterologist. They will be able to help you to safely get to the bottom of your food allergy or intolerance. 

We spoke with Kate Evans, a registered dietitian at Kelly Jones Nutrition who specializes in gastrointestinal nutrition and sports nutrition, to discuss the proper way to do an elimination diet and who can benefit from it. 

"Elimination diets are not meant to be followed forever -- instead, think of them as a controlled experiment to explore how your body responds to different foods," Evans said. 

Aside from specific foods, other factors that can be related to gastrointestinal symptoms include stress, sleep, hydration, fiber intake and meal timing. Elimination diets are just one piece of the puzzle used to address any GI symptoms you may be experiencing.

Keep reading if you're interested in learning more about elimination diets and if you're the right candidate for them.

Should you try a food elimination diet?

Usually when people do elimination diets it's to get to the bottom of a food allergy, sensitivity or intolerance. Keep in mind food allergies and intolerances are different, and symptoms may vary. 

"Food allergies cause an immediate immune response and typically present with skin or upper respiratory symptoms such as hives, itchy mouth, swollen lips, or wheezing, " Evans explained. 

Food intolerances, on the other hand, are not related to the immune system and typically don't manifest symptoms until at least a couple hours after a meal as the food moves through your digestive tract. Intolerances can cause gas, bloating and altered bowel habits. Additionally, when you have an intolerance to a food, there may be a level of intake you can handle, whereas with food allergies you should avoid it completely.

If you've been experiencing these types of symptoms you could be a good candidate for an elimination diet.

Nutrition label with allergen notice.
Getty Images/Peter Dazeley

How to get started

It's important to go through a workup with a gastroenterologist first to rule out other causes. "A gastroenterologist will perform a complete assessment including any necessary diagnostic testing and advise you on medical treatment options," Evans said. This is an essential step to take because many gastrointestinal diseases present with similar symptoms, and skipping straight to an elimination diet without meeting with a gastroenterologist can cause you to miss out on other important information about your condition.

The assessment usually involves a workup that includes blood tests, stool tests and possibly a colonoscopy or endoscopy depending on your risk factors for certain gastrointestinal diseases.

 After you've met with a gastroenterologist, you will also have to consult with a registered dietitian to determine if a food elimination diet is the right step for you.  

"Elimination diets are time consuming and difficult to follow, so it's important to discuss whether this approach is feasible with your current lifestyle and to consider whether there are other, less restrictive nutrition changes you could try first," said Evans. A registered dietitian will be able to explain if any elimination diets have been studied for your condition and guide you through the process of eliminating and reintroducing foods.

Small bowls filled with common food allergens like nuts, shrimp and eggs..

Types of elimination diets

Some popular elimination diets include Whole 30, the six-food elimination diet or the low FODMAP diet. Evans says that while the Whole 30 diet claims to improve everything from bloating, fatigue to joint pain, there's no clinical evidence supporting its efficacy in alleviating gastrointestinal issues or other symptoms.

Another elimination diet she doesn't recommend is one determined by food-specific immunoglobulin tests, also known as IgG tests. These food sensitivity tests can be done at home and are intended to determine allergies, sensitivities or a food intolerance. Evans says the American Academy of Allergy, Asthma and Immunology does not support the use of IgG tests for food intolerances. 

These kits can only detect the IgG antibody which is the immune system's normal response to eating food. "In order to detect if someone has an allergy, a blood test that checks a protein called immunoglobulin E, or IgE has to be done to create a diagnosis," Evans said. If there is proof of IgE antibodies, this indicates an immune system response -- thus an allergy is present.

On the other hand, she's seen improvement in patients with irritable bowel syndrome who do the low FODMAP diet. FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides and polyols) are a type of carbohydrate that can contribute to gas production, bloating and altered bowel habits in some people.

"This diet consists of a two- to six-week elimination phase followed by a four- to six-week reintroduction phase where each category of high FODMAP foods is added back in," said Evans. One thing to keep in mind with the low FODMAP diet is that if you do it for too long, you can risk negatively affecting your microbiome composition. However, Evans points out that more research needs to be done to better understand these risks. 

The six-food elimination diet is another method done by a gastroenterologist and is intended for those with an esophageal condition known as eosinophilic esophagitis, or EoE. "This diet eliminates and strategically reintroduces the six most common allergens over the course of several months and must be done under the supervision of a gastroenterologist, who will conduct repeat endoscopies throughout the process to assess how the esophagus is responding to dietary changes," Evans explained.

If you're a parent and think your child may have a food intolerance or allergy, Evans says there are no evidence-based elimination diets that have been designed specifically for children. "However, the low FODMAP diet and the six-food elimination diet have been studied in pediatric irritable bowel syndrome and pediatric eosinophilic esophagitis respectively with promising results," she added. 

It's important to know that these diets should always be monitored by your child's doctors. This is because children are at a critical stage of growth and development, and with elimination diets there's a risk for nutrient deficiencies and low energy intake. "If an elimination diet is medically appropriate for your child's specific situation, a registered dietitian can help minimize the risks by recommending alternative foods to replace those eliminated," said Evans. 

Patient holding their stomach in pain as doctor observes.
Getty Images/Natalia Gdovskaia

Common mistakes with elimination diets

If you try to do an elimination diet on your own, you may miss some important steps, which is why it's important to do it with the guidance of a professional. Reintroduction, for example, is commonly overlooked in elimination diets. "If you feel better after eliminating several foods, the only way to figure out which of those foods were contributing to symptoms is to systematically reintroduce them," explained Evans.

Skipping the reintroduction phase can leave you on an overly restricted diet long-term, warns Evans. Reintroductions should be done with one food or food category at a time. "By starting with a small portion of the food and gradually increasing the portion over the course of a few days, you can determine your threshold for tolerance," she said. 

You'll notice that you may be able to reintroduce some foods completely, while others may only be tolerated in small amounts or not at all. Evans points out that during the reintroduction process you may experience some gas and bloating after a meal, which is normal. However, the key here is to observe whether or not the symptoms feel the same as they did prior to doing the elimination diet. 

One other issue with doing an elimination diet on your own is the chance of choosing one that is not appropriate for your specific problem or isn't backed by research. Additionally, if you've been avoiding multiple types of foods for a prolonged period, you can put yourself at risk for nutritional deficiencies. A registered dietitian can offer food swap ideas to reduce the risk of deficiencies. "For example, someone who is lactose intolerant may have trouble meeting their calcium needs unless they are incorporating low lactose, high calcium foods to incorporate into their diet," Evans said. 

Who should avoid elimination diets

Evans warns that individuals with an active eating disorder or malnutrition are not good candidates for elimination diets because those diets can neglect your body's nutrient needs and increase anxiety around food. She explains that there has been research indicating that there may be a relationship between elimination diets and eating disorders. 

"A recent study found that children and adults with a history of following an elimination diet were three times as likely to have symptoms of avoidant-restrictive food intake disorder, an eating disorder characterized by persistent failure to meet energy needs that is driven by non-body image related factors such as anxiety about the consequences of eating or an overall lack of interest in eating," she said. 

If someone already has an existing eating disorder or similar behaviors, elimination diets could make it worse for them. That's one more reason that it's important to consult with your doctor first before doing any food elimination.

Key takeaways

If you've established that an elimination diet may help you determine whether you're experiencing a food intolerance, sensitivity or allergy, make sure you discuss with a gastroenterologist first to rule out a more serious condition. Since there are so many different types of elimination diets out there, it's important to make sure that you're doing the right one that's suitable for your needs. As with any major changes you plan on making to your diet, you should always make sure that it's done in a healthy way to avoid malnourishment or disordered eating. A registered dietitian who is well versed in elimination diets can make sure that you'll feel relief without the worry of losing out on important nutrients. If you're not sure where to begin, reach out to your general practitioner, who should be able to provide referrals to the appropriate specialists. 

The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.