Is it a Flare-Up or a Food Sensitivity Reaction? How to Figure Out the Difference

When I hear a question come up over and over again for my clients, I know it’s time to bring it up on the podcast.

Because I know if they are wondering, so are you.

One of the questions I’m getting a lot lately is, “How do I know if I’m in a true IBD flare up or if I’m just reacting to one of my food sensitivities?”

This is a great question, and on the surface, it seems like a hard one to answer. I bet, if you’ve struggled with this, it’s cost you some sleepless nights and hours of questioning.

It’s time to put this question to bed once and for all. I’ve got you covered and the answer is easier than think to figure out.

Three Things You’ll Learn in This Episode

🌿 Is there a difference between a food intolerance and a food sensitivity?

🌿 3 questions to ask yourself if you’re wondering if it’s a flare-up or a food intolerance?

🌿  How to figure out what your personal food culprits.

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Mentioned in the Episode:

Karyn’s Food-Mood-Poop Journaling System

Episode Resources:

The Eight Most Common Food Sensitivities


Food Allergy, Intolerance, or Sensitivity: What’s the Difference and Why Does it Matter?

Food Problems: Is it an Allergy or Intolerance?

Inflammatory Bowel Disease Overview

Connect With Karyn:

Karyn on Facebook

Schedule Your FREE 30-Minute IBD Consult

Episode Transcript:

Is it a Flare-Up or a Food Sensitivity? How to Figure Out the Difference

When I hear a question come up over and over again for my clients, I know it’s time to bring it up on the podcast. Because I know if they are wondering, so are you.

One of the questions I’m getting a lot lately is, “How do I know if I’m in a true IBD flare up or if I’m just reacting to one of my food sensitivities?” This is a great question, and on the surface, it seems like a hard one to answer. I bet, if you’ve struggled with this, it’s cost you some sleepless nights and hours of questioning.

It’s time to put this question to bed once and for all. I’ve got you covered and the answer is easier than think to figure out.

Let’s get into it.



Hey there my friend, how are you feeling today? It’s June and I’m happy for summer weather in Maryland—finally. I just finished planting flowers in my garden and that makes me happy too. Behind my house, I have a small garden bed and some summers I grow veggies, sometimes it’s an herb garden, and sometimes it just sits dormant when I don’t have the energy or the gumption to do anything with it. Last year my neighbor grew this amazing flower garden. It was a thing of beauty and she was always bringing bouquets over to my house. We’d take care of the garden when they traveled, I loved peering over my fence into her garden to just take in the sight of the flowers. It was a daily self-care exercise and stress reliever all in one.

So this year, I decided I’d dabble in some flowers too. I bought seeds, I grew them into little sprouts in my house and I just finished planting them this week. I know, it’s late. We’ll see what happens. I’m always late putting my garden in and it still works out so I’m hoping the flower garden works too. Sunflowers, daisy’s, zinnias, Snapdragons, and Phlox’s. If you are a flower lover, these probably mean something to you. I, on the other hand, have no green thumb and don’t have a eye for telling which flower or plant is which so this will definitely be an experiment. If it works, I should have some stress relieving, calming beauty to look and smell at during this time of year. If it doesn’t, well I tried.

What are you doing this summer to find your center, to find some peace during a troubling time with your Crohn’s or colitis? To get through the kids summer vacation. I hope you find something that makes you smile because we all deserve to find something to smile about each day and sometimes, it’s something little, but it just brightens your world for a moment. Know what I mean?

Reach out and share with me what your summer happiness goal is. I can’t wait to connect with you!

Well, my dear, this is a good episode. It’s going to provide you with some clarity on a very murky topic for many of us in the IBD world. How do we know the difference between a food sensitivity and a flare up? This can be tricky for many.


In thinking about this topic for today, like with all episodes, I wanted to give you the most medical, research backed information, but maybe this is a surprise to you and maybe it’s not, medical journals and research studies aren’t being done on this. At least not ones I could find. So today, keep in mind I’m going from my own experience and my client experiences to answer this question for you.

I do have to say though that since I started my health coaching practice back in 2010, I’ve definitely seen patterns emerge and I feel confident that you are going to benefit from what I have to share. Just keep in mind the research studies aren’t there yet. Maybe one day they will be.

Also, I want this information about flare ups vs food intolerance reactions to be very actionable for you. After this episode, I want you to be able to say, “I get it now. That makes sense and now I’ll be able to figure this out for myself.” That’s why, after just a little bit of background info to make sure we are all on the same page with what a flare up is and what food intolerance is, I’ll be giving you the 3 questions to ask yourself next time this issue presents itself to you. The three questions that will give you all the information you need to know what’s going on with you in that moment. Does that sound like a good plan? I hope it does for you.

OK, now let’s start this conversation by all of us getting on the same page. When I say, “food intolerance” or “food sensitivity” what is it that I am talking about? It’s something that every IBD client I’ve ever had has had to deal with. It’s something Gut Love Community members email me about. IBD and food sensitivities, whether you know you have them or not, are impacting how you feel. So when we say, food intolerance or food sensitivity, what are we talking about here? What’s this thing that’s impacting so many of us?


The American Academy of Allergy, Asthma, and Immunology says that, “A food intolerance occurs when someone has difficulty digesting a particular food.” The smarties at Harvard say that food intolerance is, “The inability to process or digest certain foods.” Very similar right?

Harvard talks about examples of food intolerance being something like lactose intolerance. I’ll add on to that by saying histamine intolerance or fructose intolerance. An inability to digest those things. Harvard data also says that there’s a difference between a food intolerance and a food sensitivity, though when I look at their writings about both, they are really so stinking similar that I’m not sure even they understand the difference.

Other sources that I’ve seen don’t differentiate between food intolerance and food sensitivity. They use the words interchangeably. Personally, that’s the philosophy I prescribe too. So for today, you’ll probably hear me say both words. I mean the same thing. Whether it’s a food intolerance or a food sensitivity, we’re talking about having a challenge with properly digesting a particular food.

Now even though I’m using food intolerance and food sensitivity interchangeably, I’m not including food allergies in the mix. True food allergies are quite different that a sensitivity. A sensitivity starts in the digestive system. It may branch out and show up in other places as we’ll get into today, but it starts in the digestive tract. A true food allergy is an immune response where even a microscopic amount of that food can lead to anaphylaxis—a life threatening reaction where the person has difficulty breathing, might be wheezing, trouble swallowing, low blood pressure, maybe even passing out.

Food allergies are a whole different thing as you know if you have a family member or a friend with a food allergy. That’s not what our focus is today. Today is about the food intolerance type of issue with food and frankly, the least talked about food challenge and least understood by our doctors.


So when we talk about food intolerance, what exactly are the symptoms. What do those of us with IBD and food intolerance experience as a reaction when we eat something that doesn’t agree with us?

Well, as you can image, G.I. symptoms come up.

  • Intestinal gas
  • bloating
  • abdominal pain
  • diarrhea

But food intolerance symptoms may not stop there. Like I said, even if the symptoms start in your digestive system, they may not stay there. You may never even experience gastro symptoms from your food sensitivity. And that’s what makes this so damn difficult to pinpoint, to figure out the culprit in the first place.

Your food intolerance may show up as neurological symptoms like:

  • Headaches
  • Brain fog
  • Poor concentration
  • Inattentiveness
  • Scattered mind
  • Anxiety
  • Jitteriness
  • ADHD

Or it may show up as an inflammatory response like:

  • Arthritis
  • Joint pain
  • Stiffness
  • Muscle aches
  • Runny nose
  • Sinus pressure
  • Sneezing

It may even show up as a skin response with:

  • Eczema
  • Rash
  • Bumps
  • Hives
  • Flaky patches on the head
  • Flushed skin

Your food intolerance may even show up as fatigue or drowsiness.

See why so many of us don’t know we have food intolerance? You go to your dermatologist for a rash, your neurologist for headaches, maybe a therapist for your ADHD symptoms… and not a single one of these providers puts these symptoms together. No one is looking at the whole picture, saying huh, “I wonder if there’s a root cause to all of this and I wonder if it’s all related?”

But you can begin to do that for yourself today. You can begin to ask yourself, “Which of these symptoms ring true for me and could they be related? Could something I’m eating be at the heart of all this?” These are big questions and it’s OK if you don’t have all the answers today. We start with the questions. Questions about what’s going on with you is where your healing begins.

So we can experience one or two of these symptoms after eating certain foods or more symptoms. That’s not unusual either. Probably more when it comes to food sensitivities because they can show up in different ways.


OK, so we know what the symptoms of a food intolerance or a food sensitivity are. Now let’s look at what’s going on when we have a Crohn’s or colitis flare up so we can begin to see the subtle differences. We know that an IBD flare up happens when we are not in remission, when inflammation is up, gut dysbiosis is rampant and our immune system is in attack mode. This is a time when our symptoms get out of control. As you can imagine if you remember some of the symptoms that I just mentioned, the IBD flare up is a similar picture. According to the Cleveland Clinic, world renowned for their G.I. department, they say an IBD flare up is happening when some of the following symptoms are present.

Remember our food intolerance symptoms? Keep those in mind while we go over these flare up symptoms:

  • Abdominal pain
  • Diarrhea
  • Diarrhea/constipation
  • Urgency
  • Gas
  • Bloating
  • Loss of appetite
  • Loss of weight
  • Mucus/blood in stool
  • Upset stomach

Less common, but also present sometimes:

  • Fever
  • Fatigue
  • Itchy, red eyes
  • Joint pain
  • Nausea
  • Vomiting
  • Skin rashes
  • Vision problems

Completely different right? You’ve got it now. A flare up and a food intolerance present completely different. Case closed, we can end this episode now.

Uh, not so fast. That was my way of seeing if you’re still with me.

If you saw just how similar that flare up list was and you’re comparing it to the food intolerance list, I think you see the problem coming to life right before your ears. This issue of food intolerance vs flare up is a murky, tricky, little sucker and it lies. It loves to create confusion and chaos. It’s no wonder we can’t tell the difference between a food intolerance reaction and a flare up. There’s so much overlap in the symptoms that we may think we’re having a flare up when it’s actually a food sensitivity reaction and we may think we are having a food sensitivity reaction when it’s actually a flare up.

So how do we begin to figure this out? How do we begin to peel back the layers of this seemingly complicated problem, this onion if you will, to get to what’s really going on? Because when we know what our culprit is, then we can do something about it.

Uncovering whether it’s a food sensitivity vs a true IBD flare up involves asking yourself 3 questions. Three questions that will give you the information you need to have peace of mind that you are going down the right track to address your problem.


Question #1:

When I remove my suspected food culprit, do my symptoms go away?

If this were me, and it has been me several (too many) times before, the conversation with myself would go something like, “Were there peppers in that soup I had last night, and then had again as leftovers for today’s lunch? Yes, shoot I can’t believe I did that. I know peppers and I are not friends. That must be why I’m having extra gas, bloating, and diarrhea today. That’s why my head is pounding, and my hands are aching.”

Or the conversation I’ve also had with myself in the past (I like to talk to myself a lot and I also answer back, that’s a problem isn’t it). Anyhoo, I’ve said to myself, “These last several days I haven’t felt like myself. I’ve had been on the toilet more, I can’t keep track of a single thought in my head, my gas has been really smelly, and my belly looks 3 months pregnant by 4pm. What’s going on here? What have I been eating lately? Is there a food I’ve been eating that I can attribute this too? Let me do a few days with my Food-Mood-Poop Journal and see what’s going on.”

See how those are two different scenarios, but I’m getting back to the same question. When I remove a suspected food culprit, do my symptoms go away?  And if the answer is yes, you are most likely dealing with a food intolerance and not a true IBD flare up.

Now, before we move on to question #2 I want to address the challenge I see so many of you having with IBD. You feel so awful so much of the time that you don’t know what foods to remove. You don’t have any idea where to start. I’m going to cover this in just a minute so hang tight with me. I promise I’ve got your starting place too.

But if you are already working with food to help your IBD, if you are already on a gut healing diet, if you’ve already removed many of your culprit foods, this question will be easier for you to answer.

But, if you haven’t started a gut healing diet yet, what are you waiting for? It may not be 100% the answer for you, it must be part of an IBD healing approach—it’s in that Wheel of Wellness I talk about so often on the podcast. But gut healing food is an important factor and it’s time to get started on that today. Go to Episodes 68-71, wherever you get your podcasts and listen to my gut healing diet series to help you find the best gut healing diet for you.

OK, question #1, when I remove my suspected food culprit or culprits, do my symptoms go away? Now, let’s move to question #2.

Question #2 is: What are my symptoms?

It’s time to take a hard look at what’s going on with you. It’s time to be honest with yourself about your symptoms. As moms, we so often put others needs in front of our own, so with this question we strip down all the falsehoods, all the “I’m OK, I can handle it, it’s not that bad,” and we get real and honest with ourself.

What are my symptoms?

Now, remember, those symptoms of a flare up and a food intolerance can be very similar, but we have to ask ourself, “What are my symptoms?” Although there can be a wide range of symptoms in food intolerance, usually we are not seeing things like mucus in our stool, blood in our stool, consistent weight loss, fever, eye challenges like Uveitis…

We are not seeing these types of issues with an immediate food reaction.

Are you having any of these symptoms? Remember, according to the Cleveland Clinic, these symptoms are more indicative of an IBD flare up.

But maybe your symptoms aren’t this severe. Maybe your feeling abdominal pain, you’re spending more time on the toilet, you’re having headaches and body aches… is it just a food intolerance or could more be going on?

It’s time to ask yourself question #3.

And question #3 is: How long has this been going on?

1 day? 2 days? 3 days? Or is it more like 1 week, 2 weeks, a month, or longer?

To answer this question fully, we have to know the answer to another question first and that question is, how long does a food sensitivity reaction usually last? That’s a tough one to get a definitive answer on, but let’s break this down as best we can.

First, it’s important to note that a food sensitivity reaction may occur within a couple hours of eating, but it may also occur up to 48 hours later. It also may not occur until you’ve eaten your food culprit a couple times. You may need to put a couple helpings in your system over a couple days before your body says, “Enough!”

There’s really no clear guidance from medical sources here, but from my experience, a food intolerance reaction usually will go away 1-4 days after you’ve remove the culprit.

So, how long have these troubling symptoms been going on? 1 day, 2 days… or is it a lot longer than that?

According to most IBD experts, an IBD flare up can last a week, to several months, even several years. If your challenges are going on that long and if you’ve removed all your food culprits, you better believe that’s not the cause of your symptoms. It’s time to get some help from your doctor.

So, symptoms play a role in determining what’s going on and so does how long it’s been going on. If you can answer these three questions for yourself, you will come a long way towards deciding if what you are going through is a food sensitivity reaction or a true IBD flare up.

Let’s say you’ve asked yourself these three questions and you know it’s a food intolerance that’s at play, but you just can’t figure out what’s bothering you. Where do you start? Well, there’s three options I usually suggest.


#1- Food-Mood-Poop Journal

It’s the most comprehensive, meticulous way to figure out what your food culprits are. It’s crazy powerful and why I suggest it so often to my clients and on this podcast. There’s a lot that can be gleaned from tracking your food and your responses to that food. Download an app, do a free form journal, or get my free and fabulous F-M-P Journaling System at Just get started with it and start to see the patterns in what you eat and how you feel.

Now, what’s another option if you suspect there’s some food culprits but you don’t know what they are? An elimination diet is another option to try. With an elimination diet, you get rid of known IBD culprits—the main food sensitivities for many. Eggs, dairy, gluten, corn, soy, wheat, etc… Leave them out of your eating plan for 30 days to 3 months and then start to slowly add them back in and see what happens. With an elimination diet, I highly recommend you also journal about how what you are eating is impacting you with some type of F-M-P system. We think we can keep it all in our mom brain, but we really can’t. Elimination diets can be really helpful, especially when paired with a way to track how it’s going.

Or you can do option #3. Option number three involves getting a practitioner to order a food sensitivity test for you. This is usually accomplished through a blood test and as I’ve mentioned previously on the podcast, you can now even order these kits on your own. Some are good. Some are crap. I have to say though that food sensitivity testing shows a moment in time. Our sensitivities can change over time and insurance doesn’t usually cover the testing so that can be an expensive moment in time.

If you are already working with a practitioner that has access to a high-quality food sensitivity test, go for it. If not, I highly recommend the other two methods to figure out what food intolerances you are dealing with.

Knowing what you are sensitive to will make answering those three questions extraordinarily easier.

Now, that’s what to do if you know food intolerances are at play with what’s going on with you or if you are trying to sus all that out.  But what if you know it’s a flare up. You ask yourself those three questions I mentioned and you decide, yep, I’m in a flare up. Well, now it’s time to get some help. Your gastroenterologist, your functional, integrative, or naturopathic doctor… they are trained to help you in times of flare ups so don’t suffer alone. Go see them and see how they can help.

No matter if you are suffering from food intolerances or an IBD flare up, suffering is suffering. Please do yourself a favor and start by asking questions. Ask yourself the three questions I mentioned today.

If I remove my food culprit, do I feel better?

What are my symptoms?

How long has this been going on?

Start looking at what’s going on with you—no ignoring it because you don’t have time. Trust me, ignoring it will only take time away in the long run from you being the mom, the partner, the friend, the family member, the worker, and the human you deserve to be.

Today is the day to look at what’s going on mama and I’m here to help. If you are struggling with this very thing and you’re still feeling confused about whether what’s going on with you is a food intolerance or a flare up, get in touch. Together, we’ll figure it out. is how to get in touch with me. I love hearing from you and I’m looking forward to connecting with you soon my friend!

Until we meet again, I’m wishing you a cheeky and healthy gut healing journey.

Chat soon!

These statements have not been evaluated by the Food and Drug Administration.
This podcast, video, and blog post is not intended to diagnose, treat, cure, or prevent any disease.

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