Food Intolerance Testing - What Actually Works (And What's a Waste of Money)
If you've ever Googled "do I have a food intolerance," you're not alone. It's one of the most common questions we get asked - and the answer is more nuanced than any at-home test kit will tell you.
Food Allergy vs. Food Intolerance: What's the Difference?
A food allergy is a potentially life-threatening immune response - think anaphylaxis to nuts or shellfish. If you have a diagnosed food allergy, strict avoidance is non-negotiable.
A food intolerance is different. It's mediated by different immune pathways and while not life-threatening, it can cause real, uncomfortable symptoms: bloating, gas, diarrhea, constipation, fatigue, brain fog, and more. Common examples include:
Lactose intolerance - a deficiency in the enzyme lactase, meaning you can't properly digest the sugar found in dairy.
Non-celiac gluten sensitivity - you don't tolerate gluten well, but you don't have celiac disease.
Celiac disease - an autoimmune condition where gluten triggers the immune system to attack the gut lining, flattening the villi (tiny structures responsible for absorbing nutrients like iron and B12).
Histamine intolerance - sensitivity to histamine-containing foods; very restrictive and best managed with a practitioner.
FODMAP sensitivity - a group of fermentable sugars that can trigger IBS-like symptoms including bloating, gas, reflux, and altered bowel habits.
What Food Intolerance Testing Is Actually Reliable?
Here's where it gets important. The majority of food intolerance tests on the market are not evidence-based.
What is supported by evidence:
Lactose breath test - reliable for diagnosing lactose intolerance
Fructose breath test - reliable for fructose intolerance
Celiac blood testing - but only if done correctly (you must be actively consuming gluten in the weeks prior, and ideally genetic markers are tested alongside antibodies)
What's not reliable:
IgG food intolerance panels - not supported by allergy and immunology organisations. These tests frequently return false positives, telling people they're "intolerant" to bananas, white rice, or dozens of other foods. What they're actually detecting is a reactive immune system - not a specific food problem.
The Real Issue With Food Intolerance Tests
When people get a long list of foods they "can't eat," the downstream effects are often worse than the original symptoms:
Extreme dietary restriction and nutritional deficiencies
Food anxiety that disrupts social life and eating out
The gut-brain axis gets activated, making symptoms worse
And often - the symptoms don't even improve, because the food was never the root cause
The real driver of food reactivity is usually a disrupted gut microbiome, compromised gut lining, low secretory IgA (your gut's immune defence), recent antibiotic use, or chronic inflammation. When these underlying issues are addressed, tolerance to many foods improves significantly.
What to Do Instead
Rather than cutting out foods, the goal is to understand why your gut is reacting in the first place. A thorough case history, microbiome testing, and individualised treatment plan can uncover what's actually going on - and get you back to eating freely without fear.
Because food should support your life, not control it.