Food sensitivities, intolerances, and allergies are often used interchangeably, but they actually refer to different types of reactions to food. Of the three, allergies are the best defined, yet food sensitivities and intolerances are more common than classical allergies. Here's a breakdown of each:

1. Food Allergies

The job of the immune system is to protect you from things like viruses and bacteria. But sometimes, it gets confused and treats a harmless food protein (such as peanuts or milk) as a threat.

Type of Food Allergy Reactions

IgE-Mediated Reactions (Fast and Often Severe)

Most common type.
Symptoms show up within minutes to 2 hours after eating the food.
Can lead to serious reactions like anaphylaxis which can be fatal if not treated .

What Actually Happens in the Body?

When you eat a food that your body wrongly sees as dangerous (like peanuts or eggs), your immune system makes IgE antibodies against that food. The next time that food is consumed, antibodies trigger a reaction causing the body to release histamine and other chemicals that cause inflammation and allergy symptoms.

Common Allergy Symptoms:

These can range from mild to life-threatening:

Itchy or tingly feeling in the mouth
Swelling of the lips, face, tongue, or throat
Skin rash or hives (itchy bumps)
Stomach pain, vomiting, or diarrhea
Coughing, wheezing, shortness of breath
Anaphylaxis: A very serious reaction that can cause:

Swelling in the throat
Trouble breathing
Drop in blood pressure
Shock or loss of consciousness

Anaphylaxis needs emergency treatment right away—usually with an EpiPen (epinephrine (adrenaline) injection).

How Are Food Allergies Diagnosed?

There are several tools to figure out if you have a food allergy:

Skin Prick Test: A small drop of the food protein is placed on your skin, then the skin is lightly pricked. If a bump or redness shows up, it may be a sign of allergy.
Blood Test: Measures the amount of IgE antibodies in your blood for specific foods.
Oral Food Challenge: Involving the consumption of small amounts of the suspected food under close medical supervision to watch for a reaction. It must be done in a safe setting, like a clinic or hospital.

Tests we offer at Body Fabulous include:

Allergy Blood test: This is a comprehensive allergy blood test which evaluates IgE-mediated immune responses to a broad range of foods including nuts, dairy, wheat, eggs, shellfish and airborne allergens including grass and tree pollens, dust, mould spores and more

Buy Allergy Blood Test HERE

Food Allergy & Food Intolerance Test: This test combines both IgE (allergy) and IgG (intolerance) mediated responses to commonly consumed foods to help identify which foods may be causing symptoms such as sinus congestion, gut inflammation, eczema and more.

Buy Food Allergy & Food Intolerance Test HERE

2. Food Sensitivities (aka Delayed Food Reactions)

Not all food-related symptoms are caused by classic food allergies. Some people react to certain foods in a different way. These reactions are slower, more subtle, and can be harder to pinpoint, but it can still have a big impact on how you feel.

What’s Going On in the Body?

Unlike food allergies (which involve IgE antibodies and happen quickly), these reactions:

Can involve IgG antibodies instead
Often trigger low-level, ongoing inflammation in the body
Can affect your gut health, sometimes linked to increased intestinal permeability, also referred to as “leaky gut” (where the gut lining becomes more permeable, allowing substances into the bloodstream that shouldn't be there)
Can also influence the gut-brain axis—the connection between your digestive system and your brain

What Are the Symptoms?

These reactions are often delayed. Symptoms may show up hours or even days after eating the food, which makes it tricky to figure out what’s causing them. The symptoms can also vary from person to person.

Common signs and symptoms to watch out for:

Brain fog (trouble concentrating and focusing)
Fatigue or low energy
Mood changes like anxiety, irritability, or feeling low
Headaches or migraines
Muscle or joint pain
Digestive issues like bloating, gas, constipation
Skin problems like eczema, rashes, or acne

When do symptoms happen?

Delayed onset: Symptoms can show up anywhere from a few hours to 72 hours (3 days) after eating the food.
Lasting effects: The discomfort can linger for days, especially if the trigger food keeps being eaten.

Can IgG Antibody Testing Help?

IgG testing measures your immune system’s response to foods. At Body Fabulous we offer a range of different food intolerance tests which help provide clues to identify the foods that may be contributing to your symptoms.

Food Sensitivity Test 286 Foods: This test offers a comprehensive analysis of IgG mediated immune responses to a broad spectrum of 286 foods including animal proteins, grains, vegetables, fruits, herbs and additives to help detect delayed food sensitivities that can contribute to a range of symptoms including chronic inflammation, headaches, skin issues and more

Buy Food Sensitivity 286 Test HERE

Food Sensitivity 207+ Test: This test provides a comprehensive IgG immune response analysis to 207+ foods, helping uncover hidden intolerances linked to chronic inflammation, neurological symptoms, digestive issues, and skin disorders.

Buy Food Sensitivity 207+ Test HERE

Food Intolerance 190 Foods, Candida & Yeast Test: The Food Intolerance 190 & Candida Blood Test provides a combined analysis of IgG food sensitivities and candida/yeast markers, helping to uncover triggers behind digestive discomfort, brain fog, fatigue, and skin conditions. This test is especially useful for individuals with suspected candida overgrowth, food reactivity, or chronic low-grade inflammation linked to diet.

Buy Food Intolerance 190 Foods, Candida & Yeast Test HERE

Vegetarian Food Sensitivity 161 Test: This test provides a detailed analysis of IgG immune responses to 161 vegetarian foods, helping detect delayed sensitivities often overlooked in plant-based diets. This test is ideal for individuals experiencing bloating, skin irritation, fatigue, or digestive distress despite eating clean.

Buy Vegetarian Food Sensitivity 161 Test HERE

Vegan Food Sensitivity 153 Test: This test offers a comprehensive assessment of IgG antibody reactivity to 153 vegan foods, helping to uncover delayed immune responses that may be contributing to digestive issues, skin flare-ups, fatigue, or systemic inflammation. Ideal for individuals on a plant-based diet who are experiencing unexplained symptoms.

Buy Vegan Sensitivity 153 Test HERE

How to manage food sensitivities

Support gut integrity: Focus on foods and nutrients to help the gut lining (leaky gut)

L-glutamine: An amino acid that fuels gut cells

Buy L-Glutamine supplement HERE

Zinc: Essential for tissue repair

Buy Zinc supplement HERE

Omega-3 fatty acids: Reduce inflammation

Buy Omega-3 supplement HERE

Vitamin A & D: Supports mucosal lining

Buy Vitamin A supplement HERE
Buy Vitamin D supplement HERE

Support healthy microbiome:

Probiotics – “Good” bacteria to balance your gut

Buy Probiotic Supplement HERE

Prebiotics – Foods that feed your good gut bacteria

Buy Prebiotic Supplement HERE

Polyphenols – Plant compounds found in fruits, veggies, tea, and herbs that reduce inflammation and support gut lining

Buy Polyphenol Supplement HERE

3. Food Intolerances

A food intolerance happens when your digestive system has trouble handling certain foods. This is not caused by your immune system, so it’s different from food allergies or sensitivities. Food intolerances aren’t life-threatening, but they can make you feel pretty uncomfortable.

What’s Going On in Your Body?

Most of the time, a food intolerance happens because your body is missing an enzyme that helps break down food. If that enzyme isn’t being produced (or doesn’t work properly), your body can’t fully digest certain foods.

Common reasons for food intolerance include:

Missing enzymes

If your body doesn’t make enough lactase, you’ll have trouble digesting lactose (the sugar in milk and dairy) resulting in lactose intolerance.
Buy Lactase Enzyme Supplement HERE

Chemical sensitivity

Some people react to natural chemicals in food, like caffeine or histamine. These can cause headaches, flushing, or digestive issues.
Buy Histamine Intolerance DNA Test HERE

Poor absorption in the gut

Some people can’t properly absorb fructose (a sugar found in fruits, honey, and some processed foods) resulting in fructose malabsorption.
Buy Fructose Intolerance Test HERE

Common Symptoms

Most symptoms of food intolerance affect your digestive system, and they can be:

Gas and bloating

Your body can’t break the food down, so it ferments in your gut—causing gas.

Stomach cramps or pain

Your gut muscles may spasm or become irritated.

Diarrhoea or loose stools

Undigested food draws water into your bowel or causes gut irritation.

Nausea

Especially if the food lingers in the stomach without being digested properly.

Headaches or flushing

This can sometimes happen with chemical intolerances, like reactions to histamine or caffeine.

When Do Symptoms Start?

Symptoms usually show up 1 to 3 hours after eating the problematic food.
They can also happen more gradually if you eat a larger amount of the food over time.

Struggling to manage food intolerances/ sensitivities?

Food intolerances/ sensitivities can be challenging to identify because symptoms can be delayed, varied and similar to food allergies and other conditions. If you are struggling to identify which foods may be problematic for you then an IgG test can help provide clues to help narrow things down - please see the range of tests that we offer above.

Further Support at Body Fabulous

Book a General Advice Call Here - Speak with our clinical team who can advise on the right testing or supplements based on your symptoms and needs.