WHY FOOD SENSITIVITY TESTING IS NOT WORTH YOUR MONEY

Dec 22

Let’s talk about what really works.

I need to tell you something that might be frustrating to hear, especially if you've already spent hundreds of dollars on food sensitivity testing.

“Most food sensitivity tests sold online, or offered at functional medicine clinics, are not evidence-based medicine. They're measuring something real, but not something meaningful.”

After 20+ years in practice and having navigated my own significant gut health challenges (two parents with autoimmune diseases including Celiac, myself with ileitis, gastritis, and IBS-C), I've seen countless patients come in clutching test results showing they're "reactive" to 5, 10, sometimes 20+ foods. They're overwhelmed, anxious, only eating the same five "safe" foods on rotation, and often feel worse than before they got tested.

But stick with me here. I now live with a mostly delightful digestive system, not because I eliminated anything, but because I addressed what actually matters.

The problem with IgG food sensitivity tests.

Most food sensitivity tests measure IgG antibodies to various foods. But here's what they don't tell you in the marketing materials: IgG antibodies simply indicate exposure to food, not sensitivity.

When you eat a food regularly, your immune system creates IgG antibodies to it. This is normal. This is your immune system recognizing and cataloging what you've encountered. It doesn't mean you're intolerant or that it's causing inflammation or any negative immune changes.

Scientific consensus is clear:

The American Academy of Allergy, Asthma and Immunology: "IgG antibodies to foods are commonly detectable in healthy adults and children and are not associated with disease."
The European Academy of Allergy and Clinical Immunology: "IgG testing for food allergies or intolerances is not recommended as a diagnostic tool."
The Canadian Society of Allergy and Clinical Immunology: “IgG food testing lacks both specificity and sensitivity."

What this means: If you eat eggs every morning, you'll likely test positive for IgG antibodies to eggs. Not because eggs are harming you, but because your body recognizes them as something you consume regularly. The test is essentially telling you what you eat, not what you should avoid.

And here's the cruel irony. People eliminate all their "reactive" foods, eat a restricted rotation diet for months, then retest and see "improvement" (fewer IgG reactions). But of course there are fewer reactions — you stopped eating those foods so your body stopped making antibodies to them! It's not measuring healing, it's measuring dietary restriction, which is a fast path to orthorexia (disordered eating) which I cover much more right here.

What real food sensitivities look like.

Real food reactions are observable and consistent.

Celiac Disease

An autoimmune condition triggered by gluten (the protein in wheat, barley, and rye). Symptoms include chronic diarrhea or constipation, abdominal pain, unintentional weight loss, fatigue, iron-deficiency anemia that doesn't respond to supplementation, bone loss, itchy blistering rash, and neurological symptoms. About 1% of the population has celiac disease.

Testing (while still eating gluten regularly): Tissue transglutaminase antibody (tTG-IgA), total serum IgA, and the gold standard, small intestine biopsy. If you've already eliminated gluten, genetic testing (HLA-DQ2 and HLA-DQ8) can rule OUT celiac. If you don't have those genes, you have ~99% certainty you cannot develop it. But genes can't diagnose it. While about 30% of people have the genes, only 1% develop celiac.

If you have celiac, you absolutely need to strictly avoid gluten. But if you don't, there's no evidence that eliminating gluten benefits fertility or health.

Lactose Intolerance

Your body doesn't produce enough lactase enzyme to break down lactose (milk sugar). Symptoms will occur within 30 minutes to 2 hours: bloating, gas, diarrhea, cramping, nausea.

Testing: A hydrogen breath test, lactose tolerance test, or just observation — do you consistently get symptoms within 2 hours of dairy?

Important context: You don't need to eliminate all dairy. Many people tolerate hard cheeses (which have very low lactose), yogurt (bacteria pre-digest some of the lactose), small amounts with meals, lactose-free products, or lactase enzyme supplements taken then consuming dairy.

Small Intestinal Bacterial Overgrowth (SIBO)

This is when bacteria that normally live in your large intestine overgrow in your small intestine. Symptoms include bloating (especially after meals), gas and belching, abdominal pain, diarrhea or constipation, nutrient malabsorption, and food sensitivities that develop suddenly.

Testing challenges: As mentioned, breath tests are the most common method but have significant limitations like high false positives and negatives, plus poor reproducibility. Small intestine aspirate and culture is the gold standard, but it’s invasive. So SIBO is often diagnosed clinically based on symptoms plus response to treatment.

Important context: SIBO is real, but over-diagnosed. Many people with IBS symptoms get labeled with SIBO based on a single breath test, then subjected to aggressive antimicrobial protocols. What actually helps? Addressing underlying causes (like low stomach acid, poor motility, structural issues), strategic antimicrobial treatment when truly indicated, prokinetics, stress management (the NERVA hypnotherapy app has amazing evidence to back it up), and not living on restrictive, low-FODMAP diets forever.

True IgE Food Allergies

These types of true food allergies will cause immediate, immune-mediated reactions like hives, throat swelling, or anaphylaxis. Common allergens include peanuts, tree nuts, shellfish, fish, milk, eggs, wheat, and soy.

Testing: A skin prick test or specific IgE (not IgG) blood test performed by an allergist. If you have a true IgE allergy, you know it — the reaction is immediate and obvious. You need to avoid that food and carry an epi-pen in case of accidental exposure.

Food Intolerances (Non-Allergic)

Some people genuinely react to certain foods without having allergies or celiac. Common culprits include FODMAPs (fermentable carbohydrates), histamine-rich foods, sulfites, food dyes, and MSG.

How to identify actual intolerances: Definitely not with IgG testing. Instead, with careful observation. So keep a detailed food and symptom journal for 2-3 weeks, look for patterns (does X food consistently cause Y symptom within Z timeframe), eliminate the suspected food for 2-3 weeks, then reintroduce and see if your symptoms return. For example. Raw mango seems to give my daughter horrible stomach pain. It has happened repeatedly. She now avoids raw mango, but cooked or dried seems to be fine.

The key word is consistent. If dairy bothers you sometimes but not others, it's probably not the dairy — it's your stress level, your cycle phase, or other factors. I learned this the hard way. When I was in constant stress and deep in C-PTSD, everything seemed to bother me. When I addressed my mental health and worked on healing my gut from the root up, suddenly I could tolerate foods that had seemed "problematic." The food wasn't the issue — my nervous system and gut health were.

The "Leaky Gut" question.

Intestinal permeability (the actual term for "leaky gut") is real. It happens when the tight junctions between intestinal cells become more permeable, allowing larger molecules to cross into the bloodstream and potentially trigger inflammation.

Chronic stress (huge), NSAIDs (ibuprofen, aspirin), excessive alcohol, certain infections, inflammatory bowel disease, poor sleep, high sugar diets, chronic antibiotic use are all things that can increase intestinal permeability. But you don't need expensive testing to know if your gut lining needs support. If you have chronic digestive issues, a history of regular NSAID use, high stress and poor sleep, or a history of gut infections or antibiotic exposure, then yes, supporting gut barrier function makes sense. But not through elimination diets based on questionable testing.

The middle ground? Digestive enzymes.

Here's a practical approach if you have trouble with certain foods but don't want to live in restriction.

Instead of eliminating dairy, try lactase enzyme supplements when you eat dairy, choose lower-lactose options (hard cheese, yogurt), and have dairy with meals rather than alone.
Instead of eliminating everything with fat, try ox bile or lipase supplements with fatty meals, start with smaller amounts of fat and build tolerance, and focus on easily digestible fats.
Instead of eliminating all vegetables, try digestive enzyme blends with meals, cook vegetables well rather than eating raw, and build fiber tolerance gradually.

Digestive enzymes can help you tolerate occasional splurges or build back tolerance to foods you've been avoiding. They're a bridge, not a lifetime sentence. This approach can be a game-changer — you can eat broadly and joyfully because you've addressed root causes, AND have enzyme support when needed.

How all of this matters for fertility.

Restriction creates stress, and stress disrupts fertility. The anxiety of eliminating 30 foods, the social isolation of not being able to eat with friends, the constant vigilance — these create chronic stress that directly impacts your hormones, ovulation, and nervous system regulation. Your body doesn't distinguish between tiger-chasing stress and food-anxiety stress. Both signal threat, and both tell your body this is not a safe time to reproduce.

Inadequate nutrition harms fertility. When you eliminate entire food groups unnecessarily, you risk deficiencies in calcium, vitamin D, B vitamins, iron, protein, and diverse phytonutrients. Your body needs adequate, diverse nutrition to conceive and sustain pregnancy.

Reduced microbiome diversity may harm fertility. Emerging research suggests gut microbiome diversity affects fertility, inflammation, and pregnancy outcomes. Your microbiome even influences miscarriage rates. When you eat the same limited foods repeatedly, you reduce microbiome diversity, and your gut bacteria needs variety.

The mental load takes energy from what actually matters. The cognitive and emotional energy spent tracking eliminated foods, reading labels obsessively, worrying about every symptom — that's energy no longer being spent on sleep, stress management, connection with your partner, joy, and actual evidence-based fertility interventions.

I've watched this so many times. Someone gets so consumed by food rules that they lose sight of the bigger picture. They think they’re "doing everything right" (according to the internet), but they're exhausted, anxious, and not actually feeling any better.

A practical framework to try instead.

Step 1: See Your Actual Doctor

Get tested for real things. Celiac disease (if you eat gluten regularly and have symptoms), thyroid function (hypothyroidism commonly causes constipation), H. pylori if you have gastritis symptoms, inflammatory markers (CRP, fecal calprotectin) if you have persistent issues, complete blood count, comprehensive metabolic panel.

Step 2: Observe Patterns Without Panic

Keep a food and symptom journal for 2-3 weeks, but don't use it to become hyper-vigilant. Be a calm detective and look for clear, consistent patterns. Does X food consistently cause Y symptom within Z timeframe? Do symptoms vary regardless of what you eat? Are symptoms worse during certain times of your cycle? Or when you're stressed?

If dairy always causes bloating within an hour, that's meaningful. If you feel bad sometimes after eating gluten and fine other times, it's probably not the gluten.

Step 3: Address Root Causes First

Before you eliminate anything, address the important things that harm ALL digestive function: things like chronic stress (the single biggest factor in gut dysfunction), poor sleep (gut repair happens during sleep), irregular eating (skipping meals, grazing constantly, eating in a stressed state), and excessive alcohol and NSAID use (both directly damage gut lining).

Step 4: Strategic, Temporary Elimination Only If Indicated

If you have clear, consistent reactions to a specific food, try eliminating it for 2-3 weeks and see if symptoms resolve. Then reintroduce and see if your symptoms return. Do not eliminate 30 foods based on an IgG test. Instead, eliminate the one or two foods that consistently, obviously bother you, while working more on root causes.

Step 5: Consider Digestive Support

Lactase for dairy, digestive enzyme blends for general support, ox bile or lipase for fat digestion, or betaine HCl if you have low stomach acid (please work with a practitioner on this one). These can help you maintain your all-important food variety and social connection while your gut heals.

Step 6: Work With a Practitioner Who Sees the Whole Picture

In Traditional Chinese Medicine (TCM), we assess your digestive function holistically. Do you crave hot or cold foods? Is your digestion better or worse with stress? What's your energy level after meals? How's your sleep, mood, stress? What does your tongue look like? Your pulse?

We don't need food sensitivity tests to understand your pattern. We can see it in your pulse, tongue, symptoms, and lived experience. We treat your actual pattern — like warming herbs if you're cold and tired with sluggish digestion, cooling herbs if you have inflammation, qi-moving herbs if stress is disrupting digestion, or tonifying herbs to address deficiency.

This is what holistic medicine actually means. Seeing how everything connects — your stress, your sleep, your emotions, your digestion, your fertility — and then addressing the root causes, not just eliminating foods.

My personal take, from someone who's been there.

I have diagnosed ileitis, gastritis, and IBS-C. I used to literally lay on the floor in the back of my acupuncture classrooms practically writhing in pain. I didn't poop for 7, 10, even 14 days at a time. I was constantly bloated. I cannot burp (not kidding, look it up, it's a thing!) and sadly there's only so many places where passing gas is deemed acceptable. I was miserable. ALL. the. time. I was also desperate for answers. I understand the appeal of food sensitivity testing — it promises clarity, a roadmap, and something concrete to fix.

But what actually helped wasn't eliminating foods. It was:

Addressing my trauma and mental health
Healing my gut with nourishing real foods — I ate varied soups made with bone broths and lots of veggies and grains for breakfast and lunch for several months at the start of my journey
Eating regularly and adequately — not skipping meals or restricting out of fear
Strategic use of digestive support when needed, like enzymes, occasional probiotics, L-glutamine during flares
Acupuncture and herbs tailored to my specific pattern
And yes, miralax, fiber, and hydration (although I'm still working on this last one - I swear, I’m part camel)

I still have a genetic predisposition to gut issues. I can't change my family’s autoimmune conditions or my own history. But I can live well, eat a varied diet, and have a mostly delightful digestive system by addressing what actually matters.

And so I hardly ever lay on the floor in pain anymore — like twice a year. And my gas and bloating are WAY better. And hey, I poop almost every day (but not on vacation). A true HIT PARADE of real life wins! And I'm not even joking. My quality of life is insanely better.

The bottom line.

Food sensitivity tests based on IgG antibodies are not evidence-based, and they often create more problems than they solve.
Real food sensitivities and allergies are observable, consistent, and testable through appropriate medical channels - not through mail-order tests or muscle testing.
Most people don't need to eliminate entire categories of food. Most people need to:
✓ Reduce stress (seriously, this is non-negotiable for gut health) ✓ Sleep adequately ✓ Eat regularly and varied foods ✓ Address actual medical conditions if present ✓ Stop restricting out of fear ✓ Support digestion strategically when needed
Your gut doesn't need to be "detoxed" or "cleansed." It doesn't need you to eliminate 30 foods. It needs you to feed it well, manage your stress, and trust its incredible ability to heal when given the right conditions.
If you're working on fertility, the most fertile thing you can do for your gut is stop restricting and start nourishing — both your body and your nervous system.

IgG testing is not evidence-based. Real sensitivities are observable and testable through appropriate medical channels. Your gut needs you to reduce stress (non-negotiable), sleep adequately, eat regularly and varied foods, address actual medical conditions, stop restricting out of fear, and support digestion strategically when needed. The most fertile thing you can do is stop restricting and start nourishing.

Your gut is smarter than any test. Trust it.

Nicole

TLDR Summary:

Most food sensitivity tests measure IgG antibodies, which indicate food exposure, not sensitivity - the American Academy of Allergy, European Academy of Allergy, and Canadian Society of Allergy all state IgG testing is not recommended and not associated with disease. If you eat eggs regularly, you'll test positive for IgG to eggs because your immune system recognizes them, not because they're harming you. The test tells you what you eat, not what you should avoid. The cruel irony: eliminate foods, retest months later, see "improvement" - but that's just measuring dietary restriction, not healing, which fast-tracks orthorexia.

Other bogus methods: Applied kinesiology/muscle testing performs no better than chance in controlled studies. SIBO breath tests have high false positive and false negative rates, poor reproducibility, and have become a cottage industry creating unnecessary anxiety and aggressive protocols. "Candida overgrowth" diagnosed via spit tests, stool tests showing normal candida, or vague questionnaires is not recognized by the CDC or Infectious Disease Society - the symptoms (fatigue, brain fog, digestive issues) are almost always from chronic stress, poor sleep, blood sugar issues, nutritional deficiencies, or actual medical conditions like hypothyroidism.

Real food reactions are observable and consistent: Celiac disease (1% of population, diagnosed via tTG antibody and biopsy while eating gluten; genetic testing can rule it OUT but not diagnose it - about 30% have the genes, only 1% develops celiac). Lactose intolerance (symptoms within 30 minutes to 2 hours; many people can tolerate hard cheese, yogurt, or use lactase enzymes). SIBO is real but over-diagnosed via unreliable breath tests - what actually helps is addressing underlying causes (low stomach acid, poor motility), strategic antimicrobials when truly indicated, prokinetics, stress management, not living on restrictive diets forever. True IgE allergies (immediate reactions like hives or anaphylaxis, diagnosed by allergist). Real intolerances are identified through careful observation - does X food consistently cause Y symptom within Z timeframe? If dairy bothers you sometimes but not others, it's probably your stress level or cycle phase, not the dairy.

Why this matters for fertility: Restriction creates chronic stress that directly impacts hormones, ovulation, and nervous system regulation - your body doesn't distinguish between tiger stress and food-anxiety stress. Eliminating food groups creates nutritional deficiencies (calcium, vitamin D, B vitamins, iron, protein) your body needs to conceive. Reduced microbiome diversity from eating the same limited foods may harm fertility - your microbiome even influences miscarriage rates. The mental load of tracking eliminations takes energy from what actually helps: sleep, stress management, connection, joy.

What to do instead: See your doctor for real testing (celiac, thyroid, H. pylori, inflammatory markers). Observe patterns without panic - journal for 2-3 weeks looking for clear, consistent patterns. Address root causes FIRST (chronic stress is the single biggest factor in gut dysfunction, plus poor sleep, irregular eating, excessive alcohol/NSAIDs). Make strategic, temporary eliminations only for foods that consistently, obviously bother you while working on root causes. Consider digestive enzyme support (lactase, ox bile, digestive blends) to maintain food variety and social connection - they're a bridge, not a lifetime sentence. Work with practitioners who see the whole picture (in TCM, we assess your pattern through pulse, tongue, symptoms - we don't need food sensitivity tests).

Personal experience: I have diagnosed ileitis, gastritis, IBS-C, and genetic predisposition to gut issues. I used to lay on the floor in pain, didn't poop for up to 14 days at a time, was constantly bloated and miserable. What helped wasn't eliminating foods - it was addressing trauma and mental health, healing my gut with nourishing foods (bone broth soups for months), eating regularly and adequately, strategic digestive support, acupuncture and herbs for my specific pattern, miralax and fiber. Now I hardly ever lay on the floor in pain (maybe twice a year), my gas and bloating are WAY better, and I poop almost every day. The less I restricted, the better I felt.