What is an Elimination Diet?

An Elimination Diet is a plan designed to help you to get rid of foods and chemicals to which you may be sensitive or have an allergy. The diet helps the body handle and unload  these substances. To do this an elimination diet requires the removal of certain foods or food categories from the diet.

An Elimination Diet can also be a way to test yourself for a food intolerance. In fact nutritionists see these diets as the “gold standard” for determining if an individual has a food reaction.

We all have two types of negative reactions to food. Firstly allergic reactions which act through the immune system. Secondly, sensitivities or intolerances which cover all other types of negative reactions. A key difference is that a food allergy creates an immediate immune response as a reaction to food. This reaction will happen within minutes of consuming the food. Food sensitivity because of intolerance has a delayed reaction. This can take up to a few days before symptoms are felt.

Eight food types account for 90% of all acute food allergies [Ref]:
  • Milk (lactose)
  • Egg
  • Peanuts
  • Wheat (gluten)
  • Soya and soya products
  • Fish
  • Shellfish
  • Nuts (e.g.walnuts, cashews & almonds)

At IBS Clinics we provide detailed programmes and support for Elimination Diets.

The general principle of the diet is easy to grasp and can be followed at home. However we recommend support and guidance from a nutritional therapist to ensure that the diet is as effective as possible.
Let's discuss whether this diet could be helpful for you. We can fill you in on what to expect, and what will be expected of you.

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Why follow an Elimination Diet?

Is tired how you generally feel? Do you often have gut issues like bloating or gas? Are experiencing headaches, joint pain or skin issues that medication hasn’t cleared. Food often lies behind why so many of us feel like this all the time. But GP’s can often overlook food related issues. Of course we aren’t coached to consider it by ourselves. This is where a nutritional therapist can really help improve your health and wellbeing.

We recommend elimination diets to help our patients identify their food sensitivities and see if they feel better by avoiding those foods. In fact, we’d suggest that all of us try following an elimination diet at least once. It can show us all how food types affect us and highlight if we have any food intolerances 

Often we find that people suffering from IBS have a wide range of additives or preservatives in their regular food. In particular certain food types can trigger their symptoms. Underlying this is probably the partial digestion of the food concerned. Partial digestion within the gut, sends chemical messages from the nerve system in your gut to your brain. These trigger the release of digestive enzymes, hormones and inflammatory responses.

The goal of the Elimination Diet is to cut out foods for long enough so when you add them back any reaction will be obvious.

Within the diet, keeping a food journal helps to identify trigger foods. This forms a clear guide in deciding which foods to stop eating during the later removal phase of the diet.

What to remove

The more foods covered the better the Elimination Diet. That is to say, more restrictive equals better. Of course that also equals more effort. But, in common with most things in life, the more we put in, the more we will get out.

A good diet will start by removing the 8 food types listed below. That might seem a bit overwhelming to kick-off with, but that leaves a wide array of options for people to enjoy a diet that’s satisfying. Meat and fish as well as most types of fruit and vegetables are still accessible. Follow the table below which shows examples of foods that are excluded or included during your 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
*If specific grain sensitivities are suspected it may be good to exclude these too.

So this table reflects a restrictive elimination diet. You can find plenty of sources online and in books that offer different ranges of restriction in this diet plan. If you are going to follow one of these on your own, the aim is not to get too obstinate about the details. Controlled self-experimentation is a good thing. So be prepared to try different approaches and adopt what suits you and your issues best.

That said, as cited earlier, the more food types that you eliminate, the higher chance you’ll discover the foods to which you’re intolerant. This is the aim of the diet as it’s  a positive healthy move. To this effect you should consider and test the removal of other foods that you frequently eat. For example, do you eat potatoes, bread or even granola every day? If so, try substituting them during your elimination experimenting phase. It could turn out that you have developed an intolerance to one of the staples you frequently eat. This could simply be because you’re eating it too often.

How long should you diet for?

Of course the duration of the diet may vary. Children often see benefits in around a week, while the majority of adults need to follow a diet programme for 3-4 weeks for the same level of benefits.

Whatever you do, don’t make it too complicated. Please don’t worry about calorie intake or nutrient ratios. These are minor issues during your Elimination Diet. What matters is the elimination process itself. One other important factor to keep a focus on though is to drink enough volume of water. At least 2 to 4 litres daily is necessary.

Reintroduction phase

Of course, the point is not to eliminate all the above foods forever. The aim is to eliminate them and then gradually reintroduce a food individually to enable you to monitor for any returning symptoms.

We suggest that when 3 weeks elimination has elapsed, you try reintroducing one single food group just for one day. Then spend two days monitoring your symptoms. You might try reintroducing dairy on a Monday for example. Maybe you eat some milk with cereal and eat cheese later in the day. Then spend Tuesday and Wednesday looking out for abnormal reactions to the reintroduction.

In the event of no symptoms returning, choose another food group on the Thursday and repeat the process, then do the same for all the other food groups and the culprit (if there is one) will be discovered. 

This entire process should take up approximately 5 to 6 weeks if done correctly. When the experiment is complete, you’ll have a wealth of knowledge on your body’s responses to a range of foods.


What to look for

As we all know, diet affects everything. Central to this approach is monitoring how you are feeling.You should monitor your bowel habits, digestion, sleep, mood, and energy levels,  for example.

As well as a food diary we thoroughly recommend keeping notes during the elimination phase especially and tracking and noting any and all physical, emotional or mental signs or symptoms. If your general wellbeing improves over the course of the elimination period, i.e. better sleep and more energy, better sleep, it is a strong indication that a food group you have been eating commonly is causing a problem. Equally watch out for negative and positive symptoms during the reintroduction phase. Negative reactions may include:

  • Headaches
  • Tiredness and fatigue
  • Joint pain
  • Insomnia
  • Skin Inflammation
  • Rashes
  • Bowel changes
  • Gut pain and/or bloating
  • Brain fogginess
  • Sinus or respiratory changes

Because you’ll be re-introducing foods that were eliminated one at a time, try observing food-related changes. Also anything different from how you felt during the previous three weeks could be a symptom, negative or positive.

Interestingly, some people report increased energy on reintroducing a food. But a stress response to the particular food could be causing this. And that’s a negative thing. So it’s really important to keep a log of all positive and negative reactions.

Ready to commit to an elimination diet?

Food intolerance testing is generally not offered by the NHSAlthough it is possible that your GP may encourage you to eliminate certain foods one by one, in order to identify an intolerance. You may also have read  something that inspires you online. But honestly, taking this on yourself can be slow and tricky.


Of course there are several published approaches that you could follow. However, we believe that nobody should try an Elimination Diet without some professional help and support. Apart from anything else, eliminating a large range of foods all at once could cause withdrawal symptoms, headaches, or even fatigue.

Addressing any potential underlying causes that are triggering your food sensitivity is a key part of any programme. It is by doing that you can introduce foods that may never cause a problem. Again we recommend working with a specialist nutrition professional to individualise an approach for you.

If you would like more information or advice on elimination diets or if you want to discuss your specific situation or circumstances, then please get in touch.