Both Can Be True: When Mast Cell Reactions and Food Fear Show Up Together

Content Warning: This conversation touches on orthorexia, restriction, and avoiding specific ingredients like dyes. If you've worked hard to loosen the grip of "clean" eating, please decide with care whether this is the right read for you today.

Dr. Jennifer Gaudiani is the founder and medical director of the Gaudiani Clinic in Denver, Colorado. She's board-certified in internal medicine, with an undergraduate degree from Harvard, medical school at Boston University, and residency and chief residency at Yale. Before founding her clinic in 2016, she was medical director of the ACUTE Center for Eating Disorders at Denver Health, an inpatient medical stabilization program for adults with anorexia nervosa. Her clinic offers trauma-informed outpatient care for eating disorders and undernourishment related to complex medical issues. The second edition of her book, Sick Enough: A Guide to the Medical Complications of Eating Disorders and Undernutrition, came out in late 2025.

I reached out to her because of her work on mast cell activation syndrome (MCAS), a diagnosis that so often arrives with a long list of things to avoid. What we ended up talking about was harder and more useful: how to take food reactions seriously without feeding the fear that turns eating into a minefield. That balance is hard to strike, because conversations about chronic illness tend to land in one of two camps. One camp dismisses any reaction that doesn’t show up on a test, which leaves so much of our lived experience to be discounted in the medical offices. The other camp says “natural is always better and anything artificial should be cut out, always.” That thinking has also hurt a lot of people, and I’m so cautious about perpetuating unnecessary suffering in the work that I put out into the world. Remember, plenty of natural things, like cyanide, are dangerous… natural doesn’t automatically equal better. I wanted a conversation that didn’t fall into either trap.

This topic is also personal for me. Orthorexia is an intense fear of eating, or putting on your skin, anything that isn't considered clean or natural. I grappled with it a lot in my twenties, and I still sometimes have to remind myself that food is safe and okay to eat. In fact, a lot of the “chemicals” I was scared of back then are actually things that keep our food safer because it prevents mold and dangerous bacteria from forming.

What Is Mast Cell Activation Syndrome?

Dr. G explained, everybody has mast cells, because they're part of the immune system. They live where nerve endings meet tiny blood vessels, and they cluster in the places where the outside of the body meets the inside, such as the digestive tract, eyes, skin, lungs, and genitourinary tissues. Mast cells hold hundreds of inflammatory mediators, including histamine, and ideally they only release them when something truly harmful gets in, like the welt that forms after a mosquito bite.

In MCAS, those cells are overactive and release their contents far more easily than they should. Dr. G first learned about MCAS while looking for ways to help her patients with POTS (postural orthostatic tachycardia syndrome), who felt terrible no matter what she tried. In the research, she found that many people with POTS also have MCAS, and that their POTS often can't improve until the MCAS is diagnosed and treated. If you've been told your symptoms are scattered and unrelated, overlaps like this are one reason a clinician might start to see them as connected.

How MCAS Can Turn Into an Eating Disorder

Dr. G walked me through a story she hears again and again from new patients, and it's one I've heard many versions of from people I work with. It starts with a girl who had chronic constipation as a kid, odd rashes that came and went, and more sensitivity to heat and food than her friends. By her early teens, someone has usually already told her she's too sensitive or overreacting. Then she gets her first period, and her health takes a turn. She feels achy and tired, her periods are heavy and painful, and eating starts to feel like coming down with a cold.

When she sees her pediatrician, her labs come back normal, so she ends up with a dietitian who isn't trained in eating disorders. That dietitian tells her to cut gluten, soy, and dairy, and because she's a rule follower, she does. Over time she restricts more and more, mostly because food has started to feel like a threat. As Dr. G put it, "If you end up feeling like you're allergic to food, that's just negative conditioning like any other negative conditioning."

That path can lead to anorexia, ARFID (avoidant restrictive food intake disorder), or what the DSM calls atypical anorexia, which Dr. G pointed out simply means anorexia in someone who isn't underweight. Once she has an eating disorder diagnosis, everyone tells her she'll feel better as soon as she eats enough. When, inevitably, she doesn't feel better, she starts to believe she's the problem patient and loses faith in the medical system. For clinicians, this is the moment to remember that undernutrition can be real and still not be the whole story.

Why MCAS Is So Hard to Diagnose

Part of what makes MCAS so hard to pin down is that doctors use two different sets of rules to diagnose it. The first group, called Consensus-1, counts only severe, recurring flares of a short list of symptoms. Their preferred test looks for a rise in tryptase, a substance mast cells release, during one of those flares. Dr. G pointed out the obvious problem: hardly anyone can get to a lab for a blood draw in the middle of a flare. The second group, called Consensus-2, believes the stricter rules miss many people. They count a wider range of symptoms and accept a wider range of lab tests, including histamine and prostaglandins. The catch, Dr. G explained, is that those samples have to be refrigerated and processed perfectly by a specialized lab, or the results often come back negative even when MCAS is there.

Because her clinic sees people by telemedicine across most of the country, Dr. G doesn't want patients paying for a large panel of tests that's likely to come back falsely negative. Instead, if someone has classic symptoms across several organ systems and improves on typical MCAS medications, she tells them they likely have MCAS. Some patients cry when they hear that, because they finally have an explanation. "It is dangerous to be a medical mystery," she said, because you carry the trauma of being told wrong things along with the harm of expensive treatments that don’t even help at best and do harm at worst.

When MCAS Advice Sounds Like Orthorexia

This is the part of the conversation where I got honestly uncomfortable. Dr. G tells most of her MCAS patients that there are two triggers that she believes are pretty much universal for everyone with MCAS. She says, alcohol will likely worsen their symptoms, and that synthetic FD&C dyes are also "almost always triggers for mast cell. Not always, though." Some patients realize that's why M&Ms gave them hives when a plain chocolate bar didn't.

I pushed back, because my history makes "remove this, avoid that, organic is better" lists feel loaded. We briefly discussed the bucket metaphor, which is a common way of explaining MCAS flares. The bucket metaphor pictures your body as a bucket that fills with everything your mast cells react to, like alcohol, dyes, scents, stress, heat, illness, or hormonal shifts. Each trigger adds a little more. You may handle any one of these triggers fine on its own, but when enough pile up at once, the bucket overflows and you flare.

I told Dr. G that this metaphor can be heard two ways. You can hear it as lowering your overall load so you stay below the overflow line. You can also hear it as needing to remove every possible trigger before you're allowed to heal, which is exactly where orthorexia takes hold. Dr. G agreed that tension is real, especially for people who already live with perfectionism and shame. Her answer is to name it honestly and with compassion, then treat each person's feedback as the best data available. One person might handle heat fine but crash around perfume, while another gets sick for weeks after visiting a relative's moldy house. Your own pattern matters more than any master list.

Why “Just Manage Your Stress” Is Bad Advice for MCAS

Stress is one of the things that fills the bucket, and I really appreciated how Dr. G talks about it with her patients. She called the advice to “control your stress” in order to feel better “just plain mean,” because hearing it is stressful in itself. I couldn’t agree more. Most of us with chronic illness have heard some version of that line, and it usually leaves us feeling like our symptoms are our own fault.

Dr. G takes a much more practical approach. She assumes stress is coming and plans for it ahead of time with her patients. She’ll say something like, “When it comes to exam time or the holidays, or if you get the flu, your mast cells are going to get worse. So let’s come up with sick day strategies, like bumping up your meds, so the flare isn’t as bad as it could be.” That approach doesn’t ask anyone to stop feeling stressed. It just accepts that hard seasons happen and gets a plan in place before they arrive.

That reframe made me think about travel. I love traveling, and I’m not stressed about it at all, but my body definitely is. It’s a distinction I talk about with clients all the time, because there are plenty of strategies that can help us let things roll off our shoulders a bit more. We still don’t get to control everything that stresses our bodies out, whether that’s travel, money, or the current state of healthcare.

Personally, I don’t think we’re meant to handle stress alone. If you hate cooking, the ideal world would be a community where you do the laundry and someone else does the cooking. We don’t live in that world, but I think it’s really important to work toward building more community and leaning on co-regulation instead of believing we have to get better at stress all by ourselves. If you’re living with MCAS, a plan for your hard weeks and people to share the load with will likely do more for you than another reminder to relax.


Re-Nourishing the Body When Food Feels Unsafe

For Dr. G, getting re-nourished is non-negotiable, but how someone gets there is wide open. She shared what she typically tells her own patients, while noting that it isn't formal medical advice. Many start with an over-the-counter, non-drowsy H1 antihistamine and an H2 blocker like famotidine, each usually taken twice a day. She prefers undyed pills, since the dyes and other inactive ingredients in medications can also trigger reactions. Alongside medication, she looks for a dietitian who understands both MCAS and eating disorders. Some patients also use hypoallergenic elemental shakes, and some choose temporary overnight tube feeds so their body has enough fuel to start bringing foods back.

Her goal is "the least restrictive life possible." If you never liked gluten and get enough carbohydrates from other foods, she doesn't care if you stay gluten free. If you love pasta, though, she'll work with you toward eating pasta again. When I asked how dietitians can tell whether the eating disorder or the mast cells are behind a reaction, she said, "You can't." Her advice is to believe the patient when they tell you their experience, and look at the whole day, not just the food. Were they dehydrated, overheated, underslept, or close to their period when the reaction happened? Then she asks whether they'd like to try that food again on a day when everything else is in better shape. Over time, we try our best to get enough data to develop an accurate clinical picture.

Why Going Slower Isn't Enabling

Dr. G's approach means believing patients, asking for their consent, and letting them decide when they're ready to try a food again. She said that some people would call this enabling, or say she isn't pushing patients hard enough. But she and I both agreed that this is hardly the case. She would rather go slower and gentler, because that's how she sees real progress over time. Then she said something I've rarely heard a physician say out loud. When some doctors don't see a patient improving in a straight line, they don't have the distress tolerance to sit with that uncertainty, and they start to feel bad about themselves. Instead of working through that discomfort, they hand it to the patient by saying "You're not doing it right" or "This is all in your head," which takes them off the hook.

That hit home for me, because I struggled with the same question as a newer therapist. I often wondered whether I was enabling my clients, because that’s what we are told, or simply listening to them and believing them. Now that I've been practicing for so many years, I've seen what can happen when someone stays in therapy with me for three or four years. That's a long time, but it creates a kind of change that white-knuckling or pushing past your limits never will. In the slower stretches, I've sometimes wondered whether a nervous system reset program had answers I didn't. When clients stayed long enough, the answer was usually no. If you're a clinician feeling that same pull, it may be your own discomfort with slow progress talking, not a sign that your client isn't trying hard enough.

Where to Find Dr. Gaudiani

You can find Dr. Gaudiani at the Gaudiani Clinic, which sees patients by telemedicine in almost every US state. The clinic's website also has her free blog series on MCAS. If you can't access her care, she suggests bringing the MCAS chapter of Sick Enough to a friendly nurse practitioner, physician assistant, or physician and asking them to learn it alongside you. She disclosed that she has no financial relationship with any drug, supplement, or shake company she mentioned, and that she earns only cents per book sale. Nothing here is medical advice, so please talk with your own care team before changing medications or your diet.


If you’re looking for a therapist who understands chronic illness, my directory is at thechronicillnesstherapist.com/find-a-therapist, and my workbook includes worksheets on building and trusting your medical team.

If you need a place to start, the directory on my website, thechronicillnesstherapist.com, lists therapists with lived or professional experience in chronic illness. No gaslighting allowed.

Disclaimer: Everything we discuss here is just meant to be general education and information. It's not intended as personal mental health or medical advice. If you have any questions related to your unique circumstances, please contact a licensed therapist or medical professional in your state of residence.

Destiny Davis, LPC CRC, is solely responsible for the content of this article. The views expressed herein may or may not necessarily reflect the opinions of the guest.

The content in this blog post comes directly from a real, human interview between Destiny and her guest on The Chronic Illness Therapist Podcast. This written version was formatted using AI. Listen to the full episode to hear the actual conversation.

Listen to my full conversation with Dr. Jennifer Guadiani on Ep 131: Both Can Be True: When Mast Cell Reactions and Food Fear Show Up Together

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Podcast cover art for "The Chronic Illness Therapist Podcast with Destiny Davis, LPC CRC

Listen to Jennifer’s interview with me, Destiny Davis, on Ep 131: Both Can Be True: When Mast Cell Reactions and Food Fear Show Up Together

Listen on Apple

Listen on Spotify


Dr. Jennifer Guadiani, Internal Medicine Physician, smiling in navy blue ruffled top in front of an outdoor green backdrop

Jennifer L. Gaudiani, MD, CEDS-C, FAED, is the founder and medical director of the Gaudiani Clinic. Board certified in internal medicine, she completed her undergraduate degree at Harvard, medical school at Boston University, and internal medicine residency and chief residency at Yale. Dr. Gaudiani served as the medical director for a highly specialized inpatient medical stabilization program for adults with anorexia nervosa prior to founding the Gaudiani Clinic in 2016. The Gaudiani Clinic offers specialized, trauma-informed outpatient medical care to individuals seeking support for eating disorders, undernourishment related to complex medical issues, and weight-inclusive primary care. The Clinic is based in Colorado is licensed to practice in almost every US state via telemedicine. Dr. Gaudiani has lectured nationally and internationally, has been featured on numerous podcasts, and is widely published in the scientific literature. The second edition of Dr. Gaudiani’s popular book, Sick Enough: A Guide to the Medical Complications of Eating Disorders and Undernutrition was published in November 2025, and the audiobook version that she recorded came out in February 2026.

Connect with Dr. Jennifer:

Instagram

Website


Destiny Davis, LPC CRC, smiling in a pink sweater standing outdoors with crossed arms

Meet Destiny - The host of The Chronic Illness Therapist Podcast and a licensed mental health therapist in the states of Georgia and Florida. Destiny offers traditional 50-minute therapy sessions as well as therapy intensives and monthly online workshops for the chronic illness community.

Destiny Davis (formerly Winters)

Destiny is a Licensed Professional Counselor and chronic illness educator.

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