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Why It’s Worth it to Test for At-Home Food Reactions

With Katie Knafla, RD

Katie smiling and food in the background

Season 8, Episode 3 | March 26, 2024

Food sensitivities are prevalent and problematic — and they can be hard to pinpoint without testing for them. Katie Knafla, RD, explains what food sensitivities are, what causes them, and what symptoms serve as signs that you may have them. She also how you can test for food sensitivities and offers advice for what to do to heal your gut once you get the results.

Katie Knafla, RD, is a registered dietitian and the program manager of lab testing and coaching for Life Time.

In this episode, Knafla covers some key takeaways about food sensitivities, including the following:

  • Food sensitivities are reactions that involve immunoglobulin G (IgG) antibodies. These are distinguished from food allergies, which involve IgE antibodies, and food intolerances, which occur when it’s physically hard for your body to break down a food.
  • Some people with food sensitivities may feel symptomatic right away, while others may not experience symptoms until several days later. This can make sensitivities challenging to pinpoint.
  • Most commonly, digestive symptoms are associated with food sensitivities, including intestinal bowel issues, acid reflux, and heartburn. Yet headaches and migraines, joint aches and pains, congestion, mood changes, fatigue, frequent illness, and skin issues (such as rashes, eczema, and acne) can also be signs.
  • When the single-cell layer of our gut lining becomes compromised, food particles, toxins, and bacteria can pass into the bloodstream; this can lead to food sensitivities. That’s why healing the gut is an essential part of the healing process. Knafla recommends a three-step process — remove, revive, and reintroduce — as well as targeted supplementation.
  • Food sensitivities can change over time and just because you may need to eliminate a food or food group for a period does not necessarily mean you will have to do so forever. A reintroduction phase can help you determine whether to keep the food out of your diet or enjoy in moderation.
  • Life Time offers an at-home food sensitivity test that measures for IgG reactions to 108 foods. You conduct the test at home, send it to a lab for results, and then receive a full digital report and a 30-minute consultation call with a registered dietitian to talk through your results and next steps.

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Transcript: Why It’s Worth it to Test for At-Home Food Reactions

Season 8, Episode 3  | March 26, 2024


Welcome to Life Time Talks, the podcast that’s aimed at helping you achieve your health, fitness, and life goals. I’m Jamie Martin, editor in chief of Experience Life, Life Time’s whole life health and fitness magazine. And I’m David Freeman, director of Alpha, one of Life Time’s signature group training programs.

We’re all in different places along our health and fitness journey, but no matter what we’re working toward, there are some essential things we can do to keep moving in the direction of a healthy, purpose-driven life.

In each episode, we break down various elements of healthy living, including fitness and nutrition, mindset and community, and health issues. We’ll also share real, inspiring stories of transformation.

And we’ll be talking to experts from Life Time and beyond who share their insights and knowledge so you’ll have the tools and information you need to take charge of your next steps. Here we go.


What’s going on everyone? We’re back with another episode. Today’s going to be a mini episode and the topic is going to be why it’s worth to test for food reactions. And we have a special guest, Katie Knafla. She is a registered dietitian, has been part of the Life Time corporate nutrition team for over eight years. And she currently serves as the program manager of lab testing and coaching with Life Time. Welcome Katie, how you feeling?

I’m feeling good, excited to be here.

We’re so excited to have you.

So we are talking today about food sensitivities in particular, not necessarily food allergies or food intolerances, which people have heard about and talked about. And we know we’ve done other episodes on that. So we’ll point people to our library for that. Before we dive into food sensitivities in particular, can you briefly explain the difference between sensitivities, intolerances, and allergies?

Yes. OK, I love that you brought that up. That’s a really important thing to differentiate as we’re talking today. So today we’re solely talking about food sensitivities. So those are IgG. They can either be fast acting where someone feels symptomatic right away or it can be several days later. Those are going to be non-life threatening. They can change over time. So very specifically food sensitivities is what we’re testing for and what we’re talking about today. The food allergy is going to be an IgE test. So it’s a completely different test if you were going to have it completed. And these are typically fast acting and life threatening. So, you’ll hear like with kiddos when they have like a peanut allergy and maybe they go into anaphylaxis or they get hives and they might have an EpiPen and those would be an allergy and they don’t typically change. And then the last one that’s most common would be like a food intolerance that you’ll hear people reference. And it’s typically they’re going to say, oh, I’m lactose intolerant. And that is when they’re not physically breaking down that food protein. And that is another one that’s most commonly staff fast acting, like where you would feel it right away.

And it’s usually correlated more to a GI symptom and distress and maybe they run to the bathroom quickly after that. So those are the main differences. And again, we’re being talking about food sensitivities, IgG testing, and they can absolutely change over time and aren’t typically like bricks.

Love that. So Katie, walk us through what are probably some common symptoms for food sensitivities.

Yeah, so top of mind that most people think of are those digestive things, right? Like gas, bloating, any bathroom issues, reflux, heartburn. That’s what I would say most commonly people think of, but there’s a host of other things you might be feeling. So headaches and migraines are really common. Inflammation, specifically like joint aches and pains, like if they’re like, oh, my knee’s been acting up or my shoulder’s bothering me, that might be food associated.

Skin rashes, so acne or eczema, anything along those lines. Congestion is really common, or even like a nasal drip, if that’s something you’re experiencing. Mood changes or fatigue, fat loss, plateaus, and then even frequent illness. If you’re talking with folks right now and it’s just like, oh, our house is sick all the time, or we’re experiencing a lot of illness, that could be associated with food sensitivities and gut health.

Absolutely. So what would be the cause of those? We’ve already talked about the symptoms. How about the causes?

Yeah. So plain answer is like poor gut health, right? So when you’re thinking about digestive health and what’s causing food sensitivities is you want your, so your gut lining is super long, right? Like it goes from your mouth all the way down. So you want the villi that go along that track to be really tightly packed together. Now, things that can make that digestive tract map as strong and healthy would be, let’s say, stress or eating that food that they’re very sensitive to or inflammation, which could be derived from food choices. If you’re drinking a lot of alcohol or sugar or artificial sweeteners, maybe you’ve had an antibiotic use or different medications, even overuse of disinfectants, I’m seeing that a lot more lately post pandemic. Any of those things are going to disrupt that barrier or make the gut lining more weak, which is going to lead to these food sensitivities.

Okay, so here we go. We heard the symptoms. We heard certain things that could be the causes. Now I know everybody’s probably wondering like, what’s a solution? How can we actually see or get these things tested? So we recently launched our Life Time food lab sensitivity test and if you can kind of walk us through what that is, what all it tests for and what, who would benefit from it.

Yeah. Okay. So the basis of the test is again, those IgG food sensitivities, and we’re going to test for 108 different foods. Okay. So this is available to members and non-members. It’s above 15 years of age and it’s a really simple process. They’re going to order the test online.

and it’s going to be shipped directly to their home. And this is the exciting part, it’s at home. So you get it at your house and you’re going to prick your finger and collect a blood sample and then mail it back in that prepaid envelope. And once the lab receives it, you actually are gonna get results within three days. So it’s pretty quick turnaround process. And once you get those results, something that’s really exciting that we offer is a coaching call with a registered dietitian. So you’re gonna spend 30 minutes with a dietician just looking at your personal results so that you can, really dive in and figure out how am I going to optimize my health and reach my goals, but really look under the hood and see what’s going on with you personally, because yes, we need to identify what these food sensitivities are, but we also need to help you heal that gut lining and identify why you maybe have these in the first place.

How many people actually are probably suffering from food sensitivities? Do we have like estimates out there, like in the general US population?

I wish we did. I wish there was more research. I dig into this often just because people are very curious, like, how likely is that I’m gonna have this? So there’s no good research because most people are focusing on those allergies and the fast reacting and the illness that can be associated with that obviously. But from my experience, so I worked at Life Time for eight years and that entire time I probably looked at thousands and thousands of labs. And I would, it’s very rare someone doesn’t have food sensitivity. I would say, I’ll be on the phone with someone and if they don’t have any I’d be like, wow, okay, good for you.

But, I would say it’s pretty prevalent. I’m hesitant to give you a percentage, but I would be shocked if people didn’t have food sensitivities, especially let me caveat that with if they are feeling any of those symptoms we discussed, absolutely. If they have never done some type of elimination diet, maybe they’re early on in their path to health and wellness, I would definitely want to look and I would again, be surprised if they didn’t have food sensitivities. But most commonly people are dealing with us if it’s not something they’ve looked into or dealt with before.

We, we as in Katie and I went through I food sensitivity panel and the experience from when it was shipped to me going through the process at home. I know probably some people are freaking out. Oh, I got to prick my own finger. It’s easy. It’s probably a prick your own finger doing something that was different from this. So you’ll be fine. And then from that, getting the connection on next step. So it wasn’t just interpreting what I was highly sensitive to and I’ll let Katie go into all those details, but the comprehensive game plan to correct it. And that’s one thing that I really, really enjoyed is it wasn’t just telling me what was wrong or the areas of opportunity is this is how you can correct it. So, Katie, if you can kind of share a little bit of the details behind the lab that you interpreted on me in the correction course. So let’s just can dive in on that.

Yeah, so with David’s results specifically, we have a yellow-green, yellow-red-green kind of differentiator for your results. So green means it’s not something you’re super sensitive to. Yellow, you’re kind of sensitive to it. And red is like, we need to take it out probably for like 60 days and kind of really be diligent about that. So with that, you know, it’s the first step of like, hey, let’s remove these foods. And for him, it was pea and lentil were the 60 days. And then for 30 days, the yellow was more nuts and seeds, cow dairy egg, egg yolk, and egg whites, the whole egg. So yes, we’re gonna take those foods out, but in David and I’s conversation, it was like, why are these food sensitivities coming up for you? Because we need to take these foods out, but we gotta heal your gut while we’re doing that, so that when you reintroduce these foods, you’re feeling better and able to tolerate them. So we kind of, and David, please jump in here, but we really talked about like, you know, do we need to make sure that you’re getting enough sleep and you’re recovering from your workouts because stress is the body’s perception, right? Is it from exercise? Is it from lifestyle or work? And it can come from a magnitude of things. The food sensitivities. And then how are we going to do that healing is not only with those lifestyle changes, but also with supplementation. So we talked about some probiotics and L-glutamine and we can go into more detail about that as well. And then some specialized changes for him was his protein powder. Pea protein is what you were having every single day.

So we wanted to get him on some collagen just to get that out of his diet temporarily and get something that he tolerates better. And then added some magnesium in just to support hormone balance and really that recovery and quality sleep time was another big thing if I recall from talking to you. Was there anything else that stuck out to you that you had to work on?

No, had the nail on the head. I think the eye opening piece was the pea protein because that is what I was doing every day three times throughout the day. And in my head, I was doing everything right. I was getting my protein intake and I was doing all the things that I would think would yield a great result. But if I never had the test done, I would not have been aware of what that was causing my body as far as a negative reaction. So, I mean, that was eye opening to me. So it was worth it. And that says, but more importantly, understanding how I can now repair the gut and then to what Katie just said, reintroduce after 60 days and see how the body responds to.

That’s awesome. I mean, I think that’s so interesting because, you know, we all are eating different foods all day. We tend to have our favorite things that we go to and rely on. And I had a food sensitivity test done years ago. And I remember I grew up on a beef farm in Wisconsin. And one of my sensitivities that came back was red meat. And it was beef. And I was like, oh, that we ate that all the time. And I still it kind of is my default because that’s what I’ve known. So it was interesting to have to change that, but I think it’s time for an update for myself. I’m so curious now hearing, David, what you’ve been through. But one thing I wanted to ask with that is, is the amount of sensitivities that came back for David, is that pretty average? Is it usually multiple for people or does it really depend on the individual?

It really does depend. It can vary. I wasn’t shocked. I don’t think I felt like David had so many sensitivities that I was like, oh my gosh, this is a lot. It was on like a higher end. If someone has two or three reactions, that’s not uncommon either. But what that really tells us you guys is more about your gut health. Someone that has more sensitivities or higher, let’s say they have a lot of red, or if someone has no sensitivity is, or they just have a few greens, the lesser severity and the less overall number tells us you have better gut health in general. Okay, so more sensitivities, higher levels. We need to address gut health even more strictly versus if it’s those lower numbers, it’s not as high of a concern or something we have to attack as aggressively.

So with that, do you have a 108 that’s being tested, correct?


Then what would be considered like, I guess, high, medium, low?

So let’s see here. If someone reacted in total to just green, not concerning. If it was like three or four, still not concerning. As far as like and when I say not concerning I’m not like that’s not unique. That’s not off the charts if someone has oh gosh, say five reds. I’d be like, whoa, something’s really going on here or if it’s like maybe two or three reds, but then they have five yellows. It’s again wow, that’s something we really need to address that you know on the higher end and something we need to look at so I would say yours were average number total but you had quite a handful of red and yellow so it was something we had to address which is why we added the L-glutamine for you and the probiotic, because I really wanted to heal that gut mucosal layer from that outside source just to really make sure we’re doing our due diligence there.

So you’ve kind of alluded to the three Rs that you often use with this. So you’ve kind of talked about you remove the foods you’re sensitive to, you revive the gut, which is what you’re talking about here for David with the probiotics, the L-glutamine, and then there’s the reintroduction. So I think this is what’s interesting in a differentiator, like you said about sensitivities from allergies. Like you can reintroduce these things. And how does that process of reintroduction typically go? Or how would you recommend somebody approach that? Especially if they have multiple sensitivities.

Yes. Okay. That’s a really great question. And something I would add on to that is that I want people always to follow that three step process, that reviving, because oftentimes people just remove foods and then they add them back in and then they don’t know what happened and they still feel not great. So it’s like, well, we got to do that due diligence and heal the gut. So you can reintroduce with the goal being that you can consume these foods. I never want people to leave these foods out long term. When you do go to that reintroduction process, the example I always give is, you know, after the 60 days, if you go have, you know, pizza and you’re sensitive to gluten and dairy, we’re not gonna know what the issue was, right? It’s one food group at a time. So just dairy, just gluten. So for David, we talked about he’s gonna reintroduce just the vegan protein, so the pea, and see how he does. And since these can take up to three days to feel symptoms. I don’t have you reintroduce another new food group until three or four days after. I like people to journal after your coaching call, we provide a table where you will write down your food group, how you’re feeling and the timeline of that just to make sure you can stay on track. Otherwise it does get overwhelming to kind of block yourself through that process. But the key is one new food every three or four days and then really journaling to see how you feel. Because oftentimes, and this was the case with, David, so he was not feeling super symptomatic, feeling really great. And that’s not uncommon for people is they’re like, oh, I think I’m good. And then once we take out the food, they might feel better, but not really able to pinpoint like what about them is feeling better. And then we reintroduce the food and all of a sudden, they have eggs and they’re like, oh my God, my shoulder pain is back or, oh, no, I noticed I’m congested or I get these little bumps on my cheek. It’s things like that that we’re just so used to that we don’t really say it’s a symptom until it’s gone. And then all of a sudden it comes back. It’s like, wow, that was what was doing that. So it’s really an important process to take your time through. So in the end, some of these foods you will take out longer than that 30 or 60 days just to get through that reintroduction process. But it is worth it to take that time so you can see how you’re doing and what your next steps are. It’s almost as if you’re operating in dysfunction for so long it now feels like it’s the norm to kind of like what you’re saying and then you do slowly start to introduce it back and then you’d be like, oh, okay. I do see the differences there. So it could be something subtle, but at the same time, your body obviously is always going to talk to you and let you know exactly what’s going on. So I love that you said that.

Exactly. Exactly. Well, Katie, this is a mini episode. Did we miss anything? What else do we need to cover before we sign off?

I think we did a really good job. The only thing I wanted to touch on that we didn’t talk about was some of those digestive supplements I mentioned briefly and just what they do. Okay. So we talked about like healing the gut, reviving it, and David’s doing the L-glutamine and the probiotic. So L-glutamine is amino acid that a lot of people have heard about, but we do it in a high dose so that it heals the gut. Okay. That’s what that’s for. David’s been taking it for 12 weeks. Probiotic. A lot of people are taking that. We have a very eclectic probiotic is good for a lot of different purposes and we recommend taking it before bed so it doesn’t have to compete with food in the digestive tract. But it’s going to get that good bacteria through the entire digestive tract, which is important while we’re trying to heal that stuff. And then the last thing is digestive enzymes. A lot of people will comment how they’re feeling bloated or gas or heartburn. And that’s really a sign that you don’t have enough enzymes in your stomach to break down the food that you’re consuming. So, by taking enzymes with your meals, it’s going to help you alleviate those symptoms, but also break down those foods and absorb them better. And we’ll talk about different lifestyle habits that might be important to you specifically during your coaching call, because some people, it’s because of stress or they’re eating too fast or too much liquid. So we’ll get into those specialized things, but just know there is tools that will provide you to really get you feeling great, because that’s most important to us is that you’re feeling great, you’re optimizing your health and you’re reaching your goals. And that’s really the purpose of that call. But I just wanted you all to know that there are things out there to help you with that.

That’s awesome. And that was another big takeaway. It wasn’t just suggesting the supplement, it was explaining what the supplement was going to do in reviving and repairing of all the things within the gut. So that was another great value added. So appreciate you sharing that as well.

Well, with that, we want to make sure that our listeners and viewers have a chance to dig deeper into this. They can go find resources from the training team at Life Time, including Katie as a source, at ExperienceLife.LifeTime.Life. We do have articles specifically on this topic. We also have a podcast on this topic that goes more in depth into all of those pieces. And then people, if people are interested in purchasing the at home food sensitivity kit, they can find that at Shop.LifeTime.Life. Katie, where else would you point people to either connect with you or find more info?

Yeah, definitely if you available on the site. And then you can always email us at if you have any specific questions either before purchasing or through the process and we’re happy to help. And then of course we have our Facebook community that we love answering any questions and joining people in on there too.

Great. Thank you so much, Katie. Of course. Thanks for having me.


Thanks for joining us for this episode. As always, we’d love to hear your thoughts on our conversation today and how you approach this aspect of healthy living in your own life. What works for you? Where do you run into challenges? Where do you need help? And if you have topics for future episodes, you can share those with us too. Email us at or reach out to us on Instagram, @jamiemartinel and @freezy30 and use the hashtag #LifeTimeTalks.

You can also learn more about the podcast at ExperienceLife.LifeTime.Life/Podcasts. And if you’re enjoying Life Time Talks, please subscribe on Apple Podcasts, Spotify, Google Podcasts, or wherever you listen to podcasts. If you like what you’re hearing, we invite you to rate and review the podcast and share it on your social channels too. Thanks for listening. We’ll talk to you next time on Life Time Talks. Life Time Talks is a production of Life Time Healthy Way of Life.

It is produced by Molly Kopischke and Sarah Ellingsworth with audio engineering by Peter Perkins, video production and editing by Kevin Dixon, sound and video consulting by Coy Larson, and support from George Norman and the rest of the team at Life Time Motion. A big thank you to everyone who helps create each episode and provides feedback.



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The information in this podcast is intended to provide broad understanding and knowledge of healthcare topics. This information is for educational purposes only and should not be considered complete and should not be used in place of advice from your physician or healthcare provider. We recommend you consult your physician or healthcare professional before beginning or altering your personal exercise, diet or supplementation program.

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