Food sensitivities and intolerances: How and why to do an elimination diet | Precision Nutrition

Food sensitivities and intolerances:
How and why to do an elimination diet


If you’re suffering from food intolerances or sensitivities, an elimination diet could be the most profound dietary experiment you’ll ever try.


Contrary to popular belief, food isn’t just fuel.  That’s why we hate those “would you use cheap gas in your Ferrari?” arguments for eating better.

You see, food is also information.  Every bite of food you eat sends some sort of message to your body.  And your body responds accordingly.

So, how are these messages transmitted?

Well, our gastrointestinal (GI) tract is the interface between food and body. And this huge organ system – the size of a tennis court when stretched end to end – is responsible for converting our food into chemical messages through the processes of digestion and absorption.

However, the GI tract doesn’t just digest and absorb food.

Surprisingly, the GI tract also has its own independently working nervous system (aka the enteric nervous system).  Therefore, the GI tract is rich in neurotransmitters, hormones, chemical messengers, enzymes, and bacteria. Indeed, it’s even home to 70 percent of your body’s entire immune system!

When things go wrong & how to go about fixing them

Given the amount of resources devoted to the proper function of the GI tract, it seems obvious that a healthy body starts with a healthy GI system.  Want to lose fat?  Gain muscle?  Improve sports performance?  Shine with good health and vitality?  If so, better get that GI system working properly.

But a whole lot can go wrong in the gut.  The following can wreak havoc on our GI health:

  • enzyme deficiency
  • microbial imbalance
  • motility issues
  • detoxification abnormalities
  • intestinal permeability
  • inflammation

Interestingly, food intolerance or sensitivities can contribute to every single one of these problems, either directly or indirectly.  Indeed, a growing body of evidence shows that food allergies, or more accurately food sensitivities, can harm numerous other body systems and cause a wide range of unwanted symptoms.

For example, food sensitivities/reactions and other gastrointestinal disturbances have been linked to:

  • asthma and allergies
  • autoimmune disorders
  • skin conditions
  • arthritis
  • atherosclerosis and other cardiovascular diseases
  • neurodegenerative diseases such as dementia
  • mood disorders
  • narcolepsy
  • addiction
  • migraines
  • kidney problems

Wow, that’s a huge list!  And, with more research, the list grows.  In fact, because of the number of conditions now correlated to either gut dysfunction or food sensitivities, anyone who feels like their GI system is working sub-optimally should at least consider trying a dietary approach known as an elimination diet.

Honestly, there are many ways to treat GI-related health conditions.  But the first, easiest, and most effective place to start is by eliminating or removing foods that might be causing a problem.

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The elimination diet

Obviously there’s no such thing as a perfect diet.  Biochemically, we’re all unique and have individual needs for how much to eat, what to eat, and when to eat.  Not to mention the fact that there are social and psychological components to eating well.  So we also have to do our best to find the best nutrition/lifestyle match.

However, when suffering from GI-related complaints, the elimination diet is one approach that’s extremely useful.  It addresses many of our individual needs, and benefits nearly everyone who tries it.  Plus, it’s sorta fun.  It’s like planning your own research project – on yourself.

Again, if you don’t have any gut-related complaints, there’s probably no need to experiment with an elimination diet.   Nevertheless, if you’re suffering from food sensitivities, following an elimination diet for a few weeks could be the most profound dietary change you’ll ever make. For some people, the results can feel nothing short of miraculous.

So what is an elimination diet?  Well, it’s all in the title: you eliminate certain foods for a period of time, usually three or four weeks, then slowly reintroduce specific foods and monitor your symptoms for possible reactions.

Why not just get food allergy testing done?  Well, it’s often expensive and unreliable.  Seriously, despite the multitude of currently available food allergy tests, the elimination diet still remains the gold standard for identifying food sensitivities.

As with all allergy tests, it too has its flaws.  But it’s inexpensive, easy to do, empowering (you do it, not a lab) and you experience the results first-hand, which can be a more powerful stimulus for dietary changes than a lab test.

Elimination diet philosophy and practice

Four principles guide the elimination diet plans we assign to our patients.

  1. Science: We look to the published research for data on how certain foods impact digestion and health.
  2. Experience: Although not based on published research, we use our experience to guide other recommendations.
  3. Theory: Based on both science and our experience, we come up with explanatory models for what we’re doing.
  4. Practicality: In the end, it all comes down to what people can actually stick to.

All in all, it’s easy to get very rigid, dogmatic, or restrictive with the concept of elimination diets.  And many practitioners do.  But we prefer to be guided by what actually works — as demonstrated by clinical experience and the available evidence.  So that’s what we’re going to cover today.

How to do an elimination diet

What to remove

The best elimination diets remove the largest number of foods. Generally speaking, the more restrictive the better. Yes, it’s more work. But, as with most things, the more work, the greater the payoff.

To begin with, a good elimination diet will remove gluten, dairy, soy, eggs, corn, pork, beef, chicken, beans/lentils, coffee, citrus fruits, nuts, and nightshade vegetables. That might sound like a lot, but it leaves plenty of options for a relatively satisfying diet comprised primarily of rice, meat (i.e. turkey, fish, lamb), most fruit, and most types of vegetables.

The following table gives an example of what to include and exclude during an elimination diet.

Foods to include Foods to exclude
Fruits Almost all fresh fruit Citrus fruits
Vegetables Almost all fresh raw, steamed, sautéed, or roasted vegetables Tomatoes, eggplant, potatoes (sweet potato and yams are okay)
Starch Rice*, buckwheat* Wheat, corn, barley, spelt, kamut, rye, oats, all gluten-containing products
Legumes Soybeans, tofu, tempeh, soy milk, all beans, peas, lentils
Nuts and seeds All nuts and seeds
Meat and fish Fish, turkey, lamb, wild game Beef, chicken, pork, eggs, cold cuts, bacon, hotdogs, canned meat, sausage, shellfish, meat substitutes made from soy
Dairy products and milk substitutes Unsweetened rice milk*, coconut milk Milk, cheese, cottage cheese, cream, yogurt, butter, ice cream, non-dairy creamers
Fats Cold-expeller pressed olive oil, flaxseed oil, coconut oil Margarine, butter, processed and hydrogenated oils, mayonnaise, spreads
Beverages Drink plenty of fresh water, herbal teas (e.g. rooibos, peppermint, etc.) Alcohol, caffeine (coffee, black tea, green tea, soda)
Spices and condiments Sea salt, fresh pepper, fresh herbs and spices (i.e. garlic, cumin, dill, ginger, oregano, parsley, rosemary, thyme, turmeric) Chocolate, ketchup, mustard, relish, chutney, soy sauce, barbecue sauce, vinegar
Sweeteners Stevia (if needed) White or brown sugar, honey, maple syrup, corn syrup, high fructose corn syrup, desserts

*May also be removed if you suspect specific sensitivities to grains.

As mentioned, this is a fairly restrictive elimination diet. There are lists available on the Internet allowing more, and sometimes fewer, foods in the diet. The key here is to not get too dogmatic.  Self-experimentation rules the day.  So try different things and see what works for you.

The only caveat here is that the more you remove, the more likely you are to discover foods you’re intolerant to, which is a good thing for your health.

And here’s another tip: consider removing any other foods you eat frequently. For example, eat turkey or asparagus every day? If so, try replacing them during the elimination experiment. You may find that you’ve become intolerant to one of your daily staples because you’re eating it so frequently.

How long should the diet be?

The length of an elimination diet can vary depending on your age and the severity of symptoms.  Children can usually see benefit from a 7-10 day elimination diet, while most adults seem to do well following the program for around three to four weeks.

Just don’t make things too complicated on yourself.  Macronutrient ratios, calorie intake, etc. aren’t very important during an elimination diet.  The only really important thing is to completely avoid the foods discussed above.

Also, during the elimination diet, be sure you consume adequate amounts of water.  Anywhere from 2 to 4 liters daily should do the trick.


Of course, it’s not the purpose of the elimination diet to get rid of all the foods above forever. That would be awful.  Rather, the point is to eliminate the foods and then slowly reintroduce them, one at a time, so you can monitor yourself for symptoms.

So, at the end of the three weeks of elimination, reintroduce a single food group for one day only.  And then monitor your symptoms for two days.  For example, you might decide to reintroduce dairy on a Monday.  That day you could eat some cheese, ice cream, and drink a glass of milk.  While getting right back to your elimination diet, monitor for any abnormal reactions on Tuesday and Wednesday.

If you have no observable symptoms, you may try reintroducing another food (i.e. eggs) on Thursday.  You can continue this process for a couple more weeks, reintroducing one new food every few days, until you’ve determined what foods may cause you an issue (if any).

The whole process will take approximately 5-6 weeks and, at the end of the experiment, you’ll know a heck of a lot about how your body responds to different foods.

What to look for

The key to the approach is this: pay attention to how you’re feeling.  For example, you’ll want to monitor your sleep, mood, energy, digestion, bowel habits, etc.

In fact, we recommend keeping a journal during the elimination phase and tracking any physical, mental, or emotional signs and symptoms.  If you feel better during the elimination period (i.e. more energy, better sleep), it may indicate that a food you commonly eat is causing you a problem.

The second thing to watch for is symptoms – negative or positive – during the reintroduction.  Negative reactions can include:

  • insomnia
  • fatigue
  • joint pain and/or inflammation
  • skin breakouts or rashes
  • headaches
  • bowel changes or GI pain
  • bloating
  • brain fog
  • sinus or other respiratory issues

Because you’ll be introducing eliminated foods one at a time, you can be very observant of food-related changes.  And virtually anything that is different than you felt during the previous three weeks could be a symptom, negative or positive.

Interestingly, some people actually report increased energy when a given food is reintroduced. Unfortunately this may be created by a stress response to the particular food.  And that’s actually a negative thing.  So it’s important to keep a log of all reactions – positive or negative.

Tips for success

By now you should realize that the elimination diet isn’t necessarily easy.  But it’s not that hard either.  It just requires that you have a plan and you pay attention.  Of course, the more you put into the elimination diet, the more you get out of it.  So here are some tips for having success with this plan.

  • Prepare. People who spend the week prior to starting the program looking up recipes that are elimination-diet friendly do far better than people that jump right into it.
  • Have the foods that you will need on hand. Know how to cook them, and prep as much as possible in advance. For example, making a large pot of rice, complete with vegetables, protein and seasonings ahead of time can help increase compliance during those times when you get hungry and have few options nearby.
  • Clean out your kitchen.  People aren’t particularly good with willpower. Get rid of the foods that aren’t part of your elimination phase (or hide them really well).
  • Keep a journal. Record symptoms, energy and mood throughout the day to help identify any patterns with food intake.  Remember, this is a self-experiment.  And every good scientist needs a lab book in which they can keep their notes and experimental details.


If you think you might be suffering from food intolerances, you might want to try an elimination diet.

Food has the power to promote health or create disease, and following an elimination diet can be a rewarding and eye-opening experience.

So, give it a try if you think your gut health needs a check-up. What you give up temporarily in creature comforts you’ll gain in lasting and unequivocal knowledge about your own health and wellbeing.

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