It makes sense. If food seems to trigger your symptoms, it feels logical to test for the culprits. But most of the time, it is not actually the food that is the core problem. More often, the real issue lies in how your gut is functioning and the balance of your microbiome. That is why food intolerance testing is rarely my first step.

The Problem With Intolerance and Allergy Testing

There are different tests available that look at how your immune system responds to foods, with the most common being IgE and IgG testing.

IgE allergy testing: IgE antibodies are linked to true food allergies, the kind that can cause hives, swelling, or even anaphylaxis. This type of testing is medically recognised and evidence-based. However, even IgE is not flawless. Blood tests can sometimes show false positives or sensitisation, where your immune system recognises a food but you do not actually react when you eat it. That is why a detailed clinical history, and sometimes oral food challenges, remain the gold standard for diagnosing allergies.

IgG intolerance testing: IgG measures delayed responses, where reactions can occur hours or days after eating. IgG can be valuable in guiding elimination or rotation diets, particularly for chronic or complex conditions involving gut, skin, neurological, or inflammatory symptoms. However, IgG results alone do not tell the whole story. Elevated levels may sometimes simply reflect exposure or tolerance rather than a true intolerance.

Hair or bio-resonance testing: These are not supported by strong scientific evidence. Results are often inconsistent and do not reliably line up with clinical symptoms.

So while IgE and IgG can both offer insight in certain cases, they are rarely my starting point. For most people, food reactions are not simply about the food. They are about the state of the gut.

And an important note: doing any of these tests without professional guidance can lead to unnecessary food restrictions, added stress, and even harm to your microbiome. This is something I see often when people have tested themselves and implemented long exclusion lists without looking at the bigger picture.

Why It Is Often the Gut, Not the Food

In my experience, food reactivity is usually a symptom of an unhappy gut, not the root cause.

If your gut lining is more permeable than it should be, your microbiome is out of balance, or you have SIBO, your body is much more likely to react to a wide range of foods. That does not mean those foods are bad forever. It means your gut needs support and repair.

Once we calm inflammation, restore gut barrier function, and support a healthier microbiome, many food sensitivities naturally improve or disappear.

What I Focus On Instead

Rather than starting with intolerance testing, I recommend exploring gut health with investigations like:

• SIBO breath testing, ideally including lactulose, glucose, and fructose
• Comprehensive gut microbiome stool analysis
• Intestinal permeability testing

These tests help show why your body is reacting. From there, we can create a personalised gut repair plan that tackles the root cause instead of just removing foods from your diet.

Only if symptoms persist after gut healing do I sometimes consider food intolerance or allergy testing. And in those cases, I always combine results with a guided elimination and reintroduction process so we know what is truly relevant for you.

My Advice If You Are Considering Food Testing

• Be cautious about spending big on intolerance tests before addressing gut health.
• If you already have results, do not panic. It does not mean you need to cut out every food listed forever.
• Work with a practitioner who can interpret the results in the bigger picture of your gut health.

The Bottom Line

Food intolerance testing can sometimes play a role, but for most people, it is not the first or most important step. By focusing on healing the gut itself, we often see food sensitivities improve dramatically without the overwhelm of long do-not-eat lists.

Because food is not the enemy. A resilient gut is one of the best ways to enjoy a wide and nourishing diet again.

Curious about what is really driving your food reactions? Book a consult or explore our consult and testing packages and testing bundles to get to the root cause.

References

• Stapel SO, et al. Testing for IgG4 against foods is not recommended as a diagnostic tool: EAACI Task Force Report. Allergy. 2008;63(7):793-796.
• Carr S, et al. Food allergy and intolerance. Medicine. 2018;46(3):192-198.
• Sicherer SH, Sampson HA. Food allergy: A review and update on epidemiology, pathogenesis, diagnosis, prevention, and management. J Allergy Clin Immunol. 2018;141(1):41-58.
• Uhde M, et al. Markers of non-celiac wheat sensitivity in patients with irritable bowel syndrome. Gut. 2016;65(12):1930-1937.
• Bischoff SC. Food allergies in irritable bowel syndrome: Sensitization to common food antigens does not correlate with symptoms. Am J Gastroenterol. 2004;99(4):720-728.

Written by Naturopath Chae

If you have been struggling with ongoing gut symptoms, you have probably noticed there are a lot of tests out there. Food allergy panels, intolerance tests, bloods, stool samples, breath tests. It is enough to make your head spin.

In clinic, I like to keep things clear, targeted, and effective. I do not run every test under the sun. Instead, I focus on a few that give us the most useful insights to guide your personalised gut-healing plan.

1. SIBO Breath Test

SIBO, or Small Intestinal Bacterial Overgrowth, happens when bacteria that normally live in the large intestine start growing in the small intestine. This can contribute to bloating, distention, abdominal pain, diarrhoea, constipation, and food sensitivities.

The SIBO breath test measures the hydrogen and methane gases you exhale after drinking a sugar solution. In our clinic, we use a more advanced approach that includes lactulose, glucose, and fructose to capture a fuller picture.

Why it matters: If we do not rule out SIBO, you can do all the right things for your gut health and still feel stuck. Treatment for SIBO is often very different from general gut-healing support, so this test helps us target the right approach.

2. Gut Microbiome Stool Testing

Your microbiome is like an ecosystem. A healthy gut is diverse and balanced, but if certain species are overgrown or missing altogether, it can contribute to symptoms ranging from IBS to skin issues, hormone imbalances, low mood, and fatigue.

A comprehensive gut microbiome stool test can help assess:

• Beneficial versus opportunistic bacteria balance
• Pathogens, parasites, or fungi that should not be there
• Inflammation and digestion markers
• How well the gut supports detoxification and metabolism

Why it matters: This test gives us a map of your gut so we can see what is happening beneath the surface. It helps personalise your plan, whether that includes probiotics, antimicrobials, nutritional support, or a deeper repair focus.

3. Intestinal Permeability Test

Your gut lining acts as a barrier, keeping nutrients in while blocking toxins and unwanted particles from slipping into the bloodstream. When it weakens, often called leaky gut, it can contribute to inflammation, food sensitivities, autoimmune patterns, and more.

The Lactulose:Mannitol urine test is considered the gold standard for assessing intestinal permeability. It tells us whether the gut lining is compromised and whether malabsorption may also be involved.

Why it matters: If your gut barrier is not functioning well, you can keep reacting no matter how many supplements or diets you try. This test helps us know when gut repair needs to be a priority.

What About Food Allergy or Intolerance Testing?

I get asked about this a lot. Tests like IgE and IgG panels can be useful in certain cases, but I usually reserve them for later, if at all.

IgE testing measures immediate reactions such as hives, swelling, or anaphylaxis. It is medically recognised, but blood tests can still show sensitisation or false positives. A detailed case history, and sometimes an oral food challenge, remains the gold standard.

IgG testing measures delayed responses where symptoms may appear hours or days later. It can help guide elimination or rotation diets in some chronic or complex cases, but elevated levels may reflect exposure or tolerance rather than a true intolerance.

The key point is that both IgE and IgG are tools, not stand-alone diagnoses. They should be interpreted alongside your history, symptoms, and gut-focused investigations to avoid unnecessary restriction.

My Approach

You do not need to do every test to get started. During a 1:1 consult, we can discuss which investigations are most relevant for you. Or, if you already know which tests you want, you can explore our consult and testing packages and testing bundles.

Written by Naturopath Chae