Should You Do Food Sensitivity Testing?

The Truth About Food Sensitivity Testing (And Why You're Not Alone in Wondering)

You’re eating healthy, avoiding junk, and still—your gut feels off. Maybe it’s the bloating after lunch, the brain fog by 3 p.m., or the stubborn skin flare-ups. You’ve seen those Instagram ads promising answers from food sensitivity testing. But do these tests actually work? Or are they another expensive rabbit hole?

This post cuts through the noise. As a functional health practitioner, I’ll share when food sensitivity testing can be helpful—and when it’s not the solution you’re looking for.

What Are Food Sensitivity Tests?

Most direct-to-consumer tests on the market (like Everlywell or Check My Body Health) measure IgG antibodies in your blood. These antibodies can indicate that your body has been exposed to certain foods. But here’s the catch: IgG antibodies don’t automatically mean you’re sensitive to that food. In fact, some studies show they can be a normal response to eating a food frequently.

Unlike true allergies, which involve IgE antibodies and can cause immediate reactions, IgG responses may not correlate directly with symptoms and are not considered diagnostic by most conventional allergists.

In my practice, I also offer access to professional-grade food sensitivity panels through Rupa Health. These tests provide a broader range of markers—including IgG4 and complement reactions—and are ordered and interpreted with practitioner oversight. While no test is perfect, Rupa's labs offer more clinically nuanced insights when used within a structured healing plan.

Sources: NCBI, ASCIA

When It’s Not Worth It

  • You haven’t tried a food and symptom journal. Sometimes the clearest answers come from tracking your body’s signals day by day—no labs required.
  • You want black-and-white answers. These tests are nuanced. High IgG doesn’t mean a food is harming you. Results can mislead without context.
  • You’re hoping to “fix” your symptoms without addressing gut function. Root causes like leaky gut, SIBO, or dysbiosis are often the real issue.
  • You’re not working with a qualified practitioner. Self-guided eliminations can lead to overly restrictive diets, nutrient deficiencies, and food fear.

When It Could Be Helpful

That said, food sensitivity testing may have a place—when it’s part of a structured, root-cause approach:

  • You’ve already cleaned up your diet, but symptoms persist. IgG results can highlight patterns that guide a short-term elimination protocol.
  • You’re working with a functional health practitioner who can interpret the results in context—alongside your history, symptoms, and lab markers.
  • You need a starting point to explore immune responses that could be triggering inflammation.

Used this way, IgG testing is not a diagnosis—it’s a clue in a broader investigation.

What I Recommend Instead (Or First)

Before investing in any test, I walk my clients through these foundational steps:

  1. Food and symptom tracking: Capture meals, energy, digestion, mood, and skin for 10–14 days.
  2. Remove common gut irritants: Gluten, dairy, seed oils, and ultra-processed foods—briefly.
  3. Address gut repair: Using targeted support like L-glutamine, probiotics, digestive bitters, and stress management.
  4. Reintroduce strategically: Rebuild tolerance while expanding food diversity.

This approach doesn’t just identify what’s bothering your body—it helps heal it.

Here’s How I Can Help

In my gut-focused programs, we combine functional assessments with personalized food and lifestyle strategies. If needed, I offer clinician-ordered food sensitivity testing through Rupa Health—but only when it fits into your overall care plan.

My programs also follow the LABS Framework™—a structured and proven method to address:

  • L: Lifestyle habits that support digestion and healing
  • A: Awareness of symptom patterns and food triggers
  • B: Body support through targeted supplementation and gut repair
  • S: Strategic reintroduction and sustainability practices

Want clarity on whether testing is right for you? Let’s talk.

Book a Free 15-Min Discovery Call

Disclaimer
This post is for educational purposes only and is not intended as a substitute for professional medical or mental health advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or mental health concerns.

References

  • Elson, C. O., & Cong, Y. (2012). Host-microbiota interactions in inflammatory bowel disease. Clinical & Experimental Immunology, 167(3), 282–290. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4826885/
  • Australasian Society of Clinical Immunology and Allergy. (n.d.). Food intolerance. https://www.allergy.org.au/patients/food-other-adverse-reactions/food-intolerance
  • Turner, P. J., Campbell, D. E., & Boyle, R. J. (2015). IgG4 and food intolerance – an important consideration. Current Allergy and Asthma Reports, 15(4), 1–7.
  • Jones, A. L. (2016). IgG antibodies and food intolerance. British Journal of General Practice, 66(649), 313–314.
  • Skypala, I. (2011). Adverse food reactions—an emerging issue for dietitians. Journal of Human Nutrition and Dietetics, 24(5), 385–386.

Author: Dianne Bly, Functional Health & Nutrition Consultant, RN, BSN, PN1 Nutrition, CFMP

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