When Recovery Feels Unsafe: Mast Cell Activation Syndrome (MCAS) & Eating Disorders
Written by: Allyson Inez Ford, MA, LPCC | Founder of ED and OCD Therapy
Damned if you do, damned if you don’t
“It feels like I am being punished for eating!”
“I actually want to eat [insert common fear food] now, but it’s like my body won’t let me!”
“It feels like I am allergic to the world, and everyone just keeps saying it’s my eating disorder talking.”
If any of those resonate, you might be dealing with an underlying chronic illness like MCAS, which does get triggered by certain foods, among other environmental triggers like perfume, candles, cleaning products, etc.
The double edged sword to this is that chronic restriction is also a trigger for MCAS flares. Many people describe the feeling of struggling with MCAS and an eating disorder as being trapped- damned if you do, damned if you don’t.
Your world can become very small, isolating and depressing, especially if you don’t have the support of people who believe you and advocate for you.
If you’ve ever felt worse when trying to follow standard eating disorder recovery advice, keep reading.
“I’m sure it’ll help if you are more nourished”
For many people in eating disorder recovery, eating more: expanding food variety or following a structured meal plan is supposed to lead to relief. But for some, it leads to GI pain, swelling, nausea, full body rashes, tightness in your throat, edema, joint pain, fatigue and other allergic-type reactions.
This is often misunderstood as resistance, fear, psychosomatic symptoms or worse- manipulation. This misperception is incredibly discouraging when you so desperately want to feel better, yet everyone around you seems skeptical and repeats “well I am sure it’ll help if you’re more nourished.”
When we default to dismissing clients or loved ones, we teach them they can’t be trusted and we risk missing important medical complications- like Mast Cell Activation Syndrome (MCAS). The overlap of eating disorders and MCAS is striking, and in my opinion all eating disorder providers need to be aware of the signs and symptoms. The consequences of not being aware is too devastating of a risk for those that suffer from it.
In a recent episode of Body Justice Podcast, I sat down with Dr. Jennifer Gaudiani to explore the growing recognition of MCAS in eating disorder populations, and why this matters so deeply for both clients and clinicians.
What is MCAS?
Mast Cell Activation Syndrome (MCAS) is a condition where the body’s MAST cells become overly reactive and release an allergic type of reaction.
These cells are meant to protect us. They release inflammatory chemicals (like histamine) in response to threats. But with MCAS, this system becomes dysregulated.
Instead of responding appropriately to actual allergic threats, the body begins to react to non-threatening stimuli, including:
Food (especially food with certain dyes)
Alcohol
Artificial scents from candles, oils, perfume, cleaning products, etc
Temperature changes
Stress
Hormonal shifts (onset of puberty for AFAB/ women is a common trigger due to estrogen)
Certain medications
Dust and mold
Environmental exposures- even from the water in your shower or sink!
This can lead to widespread, unpredictable symptoms across multiple body systems. Often times the reaction is painful, dysregulating and sometimes it can even be scary. When your hands suddenly swell up, nose starts running or bleeding and your skin breaks out in itchy rashes- of course you will feel concerned, uncomfortable and maybe even panicked.
You might feel angry or scared at your body and avoid even more foods, because eating seems to make things worse.
Why MCAS Matters in Eating Disorder Recovery
One of the most important takeaways from this conversation is this:
MCAS can directly interfere with eating disorder recovery and is often dismissed or overlooked.
When eating causes such intense physical distress, the body learns quickly that food is dangerous. This creates a powerful form of negative conditioning, where avoidance of food is not just psychological but also physiological.
Over time, this can lead to:
More restriction
Fearing the outcome of eating (often labeled as ARFID)
Increased anxiety around eating
Reinforcement of eating disorder behaviors
And then, a painful cycle begins:
Eating causes debiliating symptoms > Food becomes associated with harm > Overall intake decreases > Malnutrition worsens MCAS symptoms > Symptoms intensify > Providers push harder for food exposure and increasing intake > The client feels worse > Provider claims the client is psychosomatic or manipulative > Therapeutic rapport between client and provider is diminished > Client feels more alone, misunderstood and starts to doubt their own senses and self trust > Both client and provider feel stuck and hopeless.
This is where many people begin to feel deeply disconnected from their bodies. In fact, its not uncommon for symptoms of dissociation to start showing up and increasing levels of hopelessness and depression.
When Clients Are Told “It’s Just Your Eating Disorder”
Many individuals with MCAS describe a long history of being dismissed in medical and mental health settings. Even in their own families, they start to be looked at different, misperceived and blamed for “choosing” this.
Because MCAS will not be picked up on any standard eating disorder labs, labs come back “normal” - so everything must be fine, right? Wrong. MCAS is diagnosed based on a cluster of symptoms. There are certain medical tests like Serum Tryptase Test, Plasma Histamine Tests and genetic tests that may show results indicative of MCAS, but it’s not usually conclusive and can still go undetected. As you can imagine, this further erodes trust and can even lead to medical trauma.
If you’re a clinician, this is where practicing from an anti-oppression lens becomes essential. Why? Because one of the foundational values of anti-oppression therapy is believing your clients. Not assuming YOU know best about your client’s experience. When we lean in with curiosity, we can put on our detective glasses with our clients and collaborate, brainstorm and identify what we are missing.
This lens requires us to hold this truth: we can support eating disorder recovery without dismissing our clients and blaming everything on the eating disorder.
Common Symptoms of MCAS
MCAS can look different for everyone, but common symptoms include:
Flushing, hives, itchy or reactive skin
Feeling feverish or “flu-like” after eating
Digestive distress (bloating, nausea, diarrhea, edema)
Brain fog and fatigue
Rapid heart rate or dizziness (often overlapping with POTS)
Chronic pain (joints, muscles, head)
Sinus congestion or runny nose after meals
Mood shifts, including sudden depression
A key pattern: symptoms often worsen after eating or exposure to triggers.
The Overlap with Neurodivergence and Trauma
I don’t fully have the scientific answer as to “why” this is, but there is increasing recognition of overlap between MCAS and:
Neurodivergence (Autism, ADHD)
POTS (dysautonomia)
Hypermobility (Ehlers-Danlos Syndrome)
Trauma histories
From a biopsychosocial perspective, this makes sense. A person that has been under chronic stress, whether from trauma, sensory overwhelm or systemic oppression, can become more reactive over time. Neurodivergence may increase the suceptibility to sensory overwhelm.
If this resonates, you might find it helpful to explore support with your eating disorder through neurodiversity affirming therapy.
Treatment: Validation Heals and OFfers Hope
One of the most hopeful parts of this conversation is that MCAS is treatable. And often, treatment is not overly complex (though it can take time to identify your specific triggers and medication regimen).
According to my conversation with Dr. Gaudiani, early interventions may include:
Reducing environmental triggers (like artificial scents, drinking alcohol or mold exposure)
Using over-the-counter antihistamines (H1 and H2 blockers)
Supporting the body with anti-inflammatory supplements
Gradually identifying individual sensitivities
When MCAS is treated, many people experience reduced reactivity to food, increased ability to diversify intake, less fear around eating and improved trust in their body. This creates a completely different foundation for recovery and can be a life changing experience. I highly recommend receiving specialized medical support if you notice yourself in these symptoms- I will include resources below.
Rebuilding Trust with the Body
For many people with MCAS and eating disorders, recovery is about rebuilding self trust after years of being told you’re making things up, you’re overreacting, you just don’t want to recover. It’s painful and unfair that anyone with MCAS is blamed and brushed off because of this. It’s not something anyone chooses and it is not your fault. The hopeful part of this is that when you begin figuring out what helps, what treatments work for you and what your specific triggers are- you get to build a new relationship with your body, grounded in more compassion, understanding, trust and ease.
For Clinicians: A Gentle Invitation
If you work in eating disorder care, you will encounter this and you don’t have to have all the answers. None of us do. In fact, one of the most healing things you can say is: “I’m not sure what’s going on but I believe you, and I’m committed to figuring it out with you.”
That stance alone can begin to repair years of harm. I urge you to seek consultation from providers who specialize in this overlap and attend trainings on the intersection of eating disorders and MCAS. EDRD Pro has an online course on this, and The Gaudiani Clinic has a helpful blog series that you can share with clients. My podcast episode with Dr. Gaudiani may also be a sigh of relief for anyone struggling with this.
Want Support?
If you’re looking for an eating disorders or OCD therapist in CA, WA, UT, FL, MD or TN- we are here to help! We also provide eating disorder recovery coaching services worldwide.
Reccomended resources:
Gaudiani Clinic (blogs about MCAS and trusted medical care)
One Connection Healthcare (trusted medical care for EDs and MCAS)
