Top 5 symptoms of food sensitivity.
Could Your Everyday Symptoms Be Due to a Food Sensitivity?
Most people think of food reactions as dramatic: hives, vomiting, swelling, rushing to the hospital. But for many people, especially during childhood and perimenopause, food reactions are far more common and subtle.
Recent research has shown that around one-fifth of the global population experiences
some form of adverse reaction to food components. That’s nearly 20% of people dealing
with symptoms that may be linked to the way their body processes certain foods
(Amin Mousavi Khaneghah and Parisa Mostashari, 2025).
Food sensitivities can quietly influence how you feel day-to-day. They can appear as bloating, fogginess, fatigue, mood changes or skin issues and because the reactions are delayed, most people never connect the dots.
If you’ve been wondering why your body feels different or why certain symptoms keep hanging around despite eating ‘healthy food’, food sensitivity may be the missing piece.
What Exactly Is a Food Sensitivity?
Food sensitivities involve the immune system, but they’re different from allergies and intolerances.
Food allergies trigger an immediate IgE immune response (think fast, obvious and often severe reactions).
Food intolerances (like lactose intolerance) don’t involve the immune system; they’re more about enzyme deficiencies or digestive challenges.
Food sensitivities are delayed immune responses. Your body creates IgG antibodies to certain foods, and the reaction can take 6–48 hours to be felt in the body.
This delayed response makes sensitivities easy to miss. You might eat something and only notice the effects hours or even days later. And because the body is clever and adaptive, it can tolerate small exposures for a while before signalling that something isn’t quite right.
Common examples include:
Non-coeliac gluten sensitivity
Sensitivity to dairy proteins (casein, whey)
Reactions to eggs, soy, corn, food additives or even ‘healthy’ foods
Symptoms that are vague, inconsistent or difficult to track
Why do we have food sensitivities
The root cause of food sensitivities deserves a dedicated blog post, this will be coming soon.
Certain nutrients or compounds in foods, even healthy ones, can be problematic for the person who cannot fully process or tolerate them.
The science is still evolving, but researchers largely agree: food sensitivities involve an inappropriate activation of the immune system that differs from classic allergies. This immune response can send immune signals throughout the body, resulting in a wide variety of symptoms that may appear immediately or days later.
It’s not about the food being good or bad.
It’s about whether your body can handle it.
The Threshold Concept: When a Little Is Fine… Until It Isn’t
Every person has a unique threshold for each potential trigger food. Sometimes it takes only a small amount to set things off; other times it’s the cumulative exposure over days or weeks. This is why you might eat pizza one weekend and feel totally fine, then eat it another time and react. Your body is constantly — and cleverly — keeping score.
Even if you don’t notice obvious symptoms every time, your gut may still be reacting. Think of the visible symptom — like eczema — as the overflow of a full internal “bucket.” The reaction that you can visibly see is simply the last stage of the chain.
Signs Your Body May Be Reacting to Certain Foods
Skin
If you experience eczema, acne, rashes, or flare-ups that seem unpredictable, your gut may be involved. The gut and skin are deeply connected a relationship known as the gut–skin axis. When the gut microbiota is unbalanced and/or the lining becomes more permeable (leaky gut), immune responses can create low-grade inflammation that doesn’t stay in the gut.
Common presentations include:
Eczema or dermatitis
Acne or cystic bumps
Hives or rashes
Redness or irritation
Skin that simply feels reactive
The skin is one of the first places to express internal inflammation. (Rios-Carlos et al., 2024)
2. Bloating or Digestive Discomfort
Some people will notice gut symptoms first, the body will quietly and sometimes not so quietly, signal that something isn’t sitting right. When your digestive system is reacting:
You may notice bloating after meals, or a feeling of fullness that lingers long after eating.
Cramping can appear intermittently, coming and going without a clear trigger.
Your stool consistency may vary, with periods of constipation or loose stools.
Some people describe a sensation like “carrying extra weight” in their belly in the evenings.
Interestingly, you might feel relief when skipping certain foods — a subtle but powerful clue.
These symptoms aren’t just uncomfortable; they reflect low-grade inflammation and gut stress. Even if you feel fine most of the time, repeated exposure to trigger foods can keep the gut lining irritated and subtly affect nutrient absorption and overall energy.
3. Fatigue or energy crashes
Food sensitivities can silently drain your energy. Ongoing low-level immune activation is like running a hidden engine in the background, leaving you feeling depleted. Signs include:
Afternoon slumps that can’t be fixed with caffeine.
Brain fog or difficulty concentrating, even after a good night’s sleep.
Waking up tired, as if sleep didn’t refresh you.
Feeling heavy, flat, or sluggish throughout the day, even if your diet seems “healthy.”
These energy shifts aren’t just psychological they reflect the body expending energy managing inflammation. When your gut is reacting, your whole system is subtly stressed, and fatigue is often the first outward signal.
4. Headaches or migraines
Delayed immune responses to food can affect the vascular and nervous systems, sometimes triggering headaches or migraines hours later.
Some people notice pounding headaches after meals with trigger foods.
Food sensitivities can create inflammatory cascades, influencing blood vessel tone and brain chemistry.
These reactions are often delayed, making it hard to trace them back to the food eaten the day before.
Headaches may appear sporadically or in patterns, giving the illusion of randomness.
Recognising these patterns can help you link your meals and snacks to migraine triggers, offering a pathway to reduce frequency and intensity.
5. Mood changes
The gut–brain axis means your digestive system is intimately linked to mood and emotional resilience. Food sensitivities can subtly impact how you feel:
You may notice increased irritability, even in low-stress situations.
Anxiety or heightened emotional sensitivity may appear without obvious triggers.
Low resilience to stress — feeling “off” or frazzled more easily — is common.
Persistent, vague emotional shifts may actually be your body communicating internal inflammation or gut irritation.
Mood changes are often overlooked because they seem intangible, but they are real physiological responses to immune activation in the gut. Supporting your gut and identifying trigger foods can help restore more balanced, predictable emotional states.
Why This Matters: The Role of Low-Grade Inflammation
Food sensitivities create low-grade, chronic inflammation in the gut. This may be subtle, you may not feel sick, but over months or years it contributes to:
Gut permeability (leaky gut)
Worsening of perimenopause symptoms
Hormonal imbalance
Blood sugar instability
Joint pain
Brain fog and mood issues
Skin flare-ups
Poor nutrient absorption
When the gut is irritated, your whole system feels it and this is why identifying sensitivities can be absolutely transformative.
How Identifying Sensitivities Can Help You Feel Better
When you remove (or reduce below your threshold) the foods causing irritation, you often see:
Calmer digestion
More stable energy
Clearer skin
Better sleep
Fewer headaches
Less anxiety
Improved hormonal symptoms
A general feeling of lightness and ease
This is the exact reason I teach these concepts in clinic and why I’m building a structured, supportive course around this for next year.
When you understand the why, you regain trust in your body.
When you understand your triggers, you get your vitality back.
The Takeaway
Understanding your personal food triggers can:
Reduce inflammation
Support hormones
Improve digestion
Clear your skin
Stabilise your mood
And give you back the energy you’ve been missing
If you’ve been wondering why you feel off, this may be your sign to explore whether food sensitivity is at play.
References
Amin Mousavi Khaneghah and Parisa Mostashari (2025). Decoding food reactions: a detailed exploration of food allergies vs. intolerances and sensitivities. Critical reviews in food science and nutrition, 65(14), pp.1–45. doi:https://doi.org/10.1080/10408398.2024.2349740.
Rios-Carlos, M., Cervantes-García, D., Córdova-Dávalos, L.E., Bermúdez-Humarán, L.G. and Salinas, E. (2024). Unraveling the gut-skin axis in atopic dermatitis: exploiting insights for therapeutic strategies. Gut Microbes, 16(1). doi:https://doi.org/10.1080/19490976.2024.2430420.