How do you know if you have food intolerances or food sensitivities? Find out the definition of a food intolerance and two ways to discover if you have one.

This week, I’m taking a deep dive into some of the basics around food intolerances and food sensitivity testing with a series here on the blog.
Yesterday, we talked all about the symptoms of food intolerances and how long you can expect the symptoms to last.
You can see the previous posts in this series here:
Today, we’re going to discuss the idea of “how do you know if you have a food intolerance?” We’re going to revisit the definition of food intolerances, so we’re on the same page, then dive in to the different ways to identify food intolerances in YOUR body.
Finally in this post, we’ll cover the question “Can you test for food intolerances?”
But first things first – I want to make my disclaimer about this blog series and why I teach what I teach here on my blog and website:
I don’t think there’s one way of eating that’s better for anyone. I don’t promote a gluten-free dairy-free diet because it’s somehow HEALTHIER than other diets.
I talk about it because I eat that way (egg-free too), and it seems to resonate with a lot of women out there.
I feel like there’s not enough info out there for women getting started with this diet when they discover they can’t eat certain things, so I do my best to share my journey, my tips, and things I’ve learned along the way.
The goal here is to shorten the learning curve, not preach what I do because I think others should do it too.
Take note that I’m not a doctor and this is not medical advice. I’m a certified health coach and person who’s been living with food intolerances for years, that’s it. I’m just a person who’s trying to share information.
If you need medical advice or specific health advice, be in touch with your doctor or naturopath who can give you a personal diagnosis.
Ready to dive in? Let’s get to it!
First things first, let’s define what a food intolerance is. We talked more about this in the first part of this series, and you can revisit that for more info if you’d like, but for now, let’s look closely at my definition of a food intolerance.
Food intolerance definition
A food intolerance or food sensitivity is an immune system response in the body when a certain food is eaten.
This response is known as an IgA or IgG antibody response, and is a delayed reaction to eating specific foods that your body cannot break down properly.

These reactions often comes in the form of digestive issues, skin issues, and even mood related symptoms.
We’ll talk more about food intolerance symptoms in another blog post, but for now, know that almost anything that is strange going on in your body that you can’t explain can often be explained by a food intolerance.
Now that we’re on the same page and we know what a food intolerance is generally speaking (again, go back to parts 1 or 2 for more info on what lead us to today’s discussion), let’s talk about figuring out if YOU have any food intolerances.
How do you know if you have a food intolerance?
The first answer here is you listen to your body. You listen to any signs and symptoms that your body has been sending you that feel maybe a little bit (or a lot) “off” in your system.
Click the link for a list of potential food intolerance symptoms or check out the food intolerance symptoms chart below.
Food Intolerance Symptoms Chart
You can simply start noticing things in your body that don’t seem like everyone is dealing with them on a regular daily basis.
Symptoms like headaches, achy joints, skin issues like acne or eczema, or ongoing digestive issues like constipation, bloating, and diarrhea.
You can write these symptoms down in a journal and just start keeping a running list for a little while if you like.
Or you can just do a quick body scan every once in a while and realize that maybe you have something larger going on that you’d like to dig into deeper.
After a general awareness that you may have a food intolerance or food sensitivity, the next step is to ask yourself “what’s really going on here?” Come at it with a curious mind.
Instead of trying to specifically identify whether or not you have a food intolerance, start to think about any other things that might be causing your ongoing symptoms.
It could be anything from your regular exercise routine to what laundry soap you use. Think through if some of your actions elsewhere in your life could be causing the symptoms you have.
One way to dig deeper into determining if you have a food intolerance is to go to a doctor’s office and try to get an official diagnosis.
For this type of conversation, you’d simply go in and discuss the possibilities, tell them the symptoms you’re facing, and then talk about potential ways to determine once and for all if you have food intolerances.
I did this exact thing back in 2011. I was having both back pain and digestive issues regularly, and I brought in my top-of-mind laundry list to a brand new doctor and asked him what was going on with me.
First, he determined that I have one leg that is slightly shorter than the other (Huh? But okay, fair enough) and that was likely causing my back pain.
Secondly, after pressing him for answers to my digestive issues of ongoing bloating, gas, gas pains, hemorrhoids, diarrhea and constipation that were coming and going, he told me to try food journaling.
Try wheat and gluten first. Then after pressing further about the hemorrhoids, he said “try to cut out dairy and see how you do after that.”
I was given my marching orders, but no real diagnosis.
The thing about food intolerances is that no one can really TELL you what’s going on with you. Not even a doctor. They can make an educated guess. They can give you a jumping off point, but really at the end of all of it, you have to figure it out yourself!
Which leads me to the two ways you can truly find out if you have a food intolerance – and how to figure it out yourself.

Way #1. The Elimination Diet
An elimination diet is simply taking a good look at what you’re eating, then systematically removing one food at a time and bringing it back into your diet to determine if you have any adverse reactions to that food.
There are many programs that suggest that you need to cut out all major food allergens at once. After cutting them out, you slowly add them back in to your diet one at a time.
Let me tell you, it’s not necessary and it’s freaking hard to follow through with. I only made it 5 days without all top 8 allergens, meat, nightshade vegetables, and citrus fruits before I couldn’t continue on.
An elimination diet is simple, because you can do it at home, on your own time, using your own food. For this discussion, the elimination diet is what Im calling the free way to discover your food intolerances, because yeah, its free. And it works.
How To Do An Elimination Diet in 6 Easy Steps
The steps to conduct your own elimination diet are basic and straightforward. Heres what you need to do:
1. Start keeping a food journal
You can start with a few days or a few weeks whatever really feels right to you. Just write down what you eat and when.
Then as you make your way through the day, if you notice any weird symptoms (like brain fog or headaches), you can write down when you start to feel them.
If you’re one for keeping track but know you wont stick with it without something tangible in front of you, check out this great food journal to help you along the way.
It’s thorough and you can keep this with you over this process to narrow down any patterns you find.
This isn’t AT ALL about judging your food choices. I know many people think that food journals are a way to make you super aware of what you’re eating and it brings up all kinds of shame but don’t do that.
Just write down what you eat and be honest about it. Your body will thank you later.
2. Look for patterns between symptoms and foods
Notice that you always get headaches after eating bread? Or find yourself constipated three days after having milk?
Look for any obvious patterns that emerge and take note. It might not be as obvious as you’d like it to be. And if it isn’t that’s okay. Just keep tracking until you start to get an idea as to what foods are triggering your symptoms.
3. Choose one food to remove from your diet and do it
Take a food out of your diet ONE at a time and see how you feel for about 2 weeks.
If that food is a culprit for some of your symptoms, you will probably start feeling better within a few days. You’ll want to keep it out of your diet for longer than just when you start feeling better though. Give it at least two weeks.
Only take one food out at a time otherwise you’re going to feel like crap, because not only will you feel totally deprived and like you can’t eat ANYTHING, but it will help you tease out the specific foods that you have reactions to one at a time.
If you take five foods out all at once, you’ll never know which one made you feel bad and the other four could have stayed in your diet.
4. Bring the food back in gently and methodically
So you’ve had the food out of your diet for a few weeks if you’re feeling better, awesome! Thats crazy good news! If you’re not, well then you may have some more elimination tests to do.
This is the part that’s not so fun. That’s because your body hasn’t had the food in two weeks and your reaction to it (if you have an intolerance) might come back in full force. You might have a super strong reaction and that sucks.
But! The bright side is that you’ll know exactly what one food is that you’re intolerant to and you can move forward without eating that food any longer.
Bring the food back into your diet gently if you’re testing gluten, start with one piece of bread for three days in a row then wait a week.
It’s important to not go crazy with the food once you bring it back, because you’re looking for all symptoms in its most extreme and most subtle forms.
5. Watch for your reactions
Wait a week after bringing the food back and tune in to your body. Bring the food journal back in so that you’re acutely aware of what’s going on in how you feel.
Remember reactions of a food intolerance are not always just physical they can be mental (like brain fog) or emotional (like you feel like you’re becoming the Hulk) too.
6. Make your determination and repeat the process
By this point, you probably feel at least slightly confident as to whether or not you have an intolerance to a food or not. If you do, you’ll want to remove that food from your diet completely. If not, then reintroduce it back into your diet as you would normally.
If you’re still having symptoms of food intolerance or reactions you just can’t explain, repeat the process over again until you find the culprit.

Okay, now that you know the basics steps for how to conduct an elimination diet, let’s talk about the time investment for this option.
As for how long it takes, well, that can depend on how much time you want to keep a food out of your diet before bringing it back in to test your reactions. It also depends on how many different foods you test in and out of your diet.
If you only wind up testing gluten, dairy, eggs, tree nuts, peanuts, shellfish, fish, and soy (these are the top 8 most common allergens), it can take you a couple months overall.
If you want to go deeper if you aren’t seeing your symptoms dissipate with every food intolerance you discover, then you might want to try even more foods based on whats coming up in your food journal.
The bottom line: doing your own research into your body’s food intolerances is simple to do at home and free using detailed food journaling and tracking. But it may take you a long time and effort to adjust and readjust your diet multiple times over.
Way #2: The Food Intolerance Test Way
A blood food intolerance test is a super simple way to discover your food intolerances by taking a sample of your blood, then sending it off to a lab to assess your food intolerances.
This test is based on the reactions to a set of potential food triggers, and you’ll find out which foods you may have a food intolerance to all at once.
Instead of working through them one at a time like you would with an elimination diet, you will have a comprehensive set of foods to use as a starting point to make informed decisions about how you change your diet moving forward.
The blood sample collected is tested among a set panel of potential food triggers (a standard panel is around 96 different foods).
This test will measure the IgG (autoimmune reaction) level in response to being exposed to each and every food in the panel.
Once your results have been documented, you’re notified of which foods you’re intolerant to and you can make changes to your diet.
You can check out how a food intolerance test is conducted by watching this video of my EverlyWell food sensitivity test on this page.
So now that you know the two real ways to discover if you have a food intolerance, or at least help point you in the right direction, next we should talk about if you can TRULY test for a food intolerance.
Can you test for a food intolerance?
The answer is yes, but it’s also a little gray. Let me explain.
There has been some controversy among some health providers around the validity of food intolerance testing, stating that there really isn’t a true way to test for food intolerances.
I think that while there may be some truth that identifying food intolerances can be extremely difficult and isn’t just boiled down to a blood reaction, I think there can be some immense value in taking a blood test for further direction.
In my experience of feeling completely overwhelmed with what was going on in my body, I needed a little bit of guidance of where to start when it came to changing my diet. I had done elimination diets for months.
I had tried cutting out foods and bringing them back in. I had tried journaling and journaling about what I was eating, but I had no real reason for why I was breaking out in hives every day for 6 weeks.
After taking a blood test, I learned that I was also intolerant to eggs, a food that I had never in my wildest dreams thought that I’d had reactions to.
When it comes to the validity of these tests, I think if you’re at the point of feeling overwhelmed with no direction on which way to go, taking a bit of a shortcut to discover which foods you could be really focusing in on taking out of your diet is worthwhile information.
Whether it’s 100% accurate or not seems like less of a priority to me than figuring out what actions I can take to start feeling better as quickly as possible. Any small step to get me closer to that is valuable.
So you might be wondering, “how do doctors test for food intolerance?” The answer is simple. They use the same technology as the rest of us do in these at-home kits. They test for IgA and IgG immune responses.
The validity of these tests is the same whether a doctor administers it or you do it yourself.
We’ve covered a lot today! Tomorrow we’ll continue on in this series with the topic of “Is food sensitivity testing right for me?”
We’ll dive in to choosing a test that’s right for you, the cost of at-home food sensitivity tests, and the top 10 ways to know it’s the right choice for you on your journey towards determining your own food intolerances. It’s going to be a good one, don’t miss it!
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