What is a Food Sensitivity vs. Food Intolerance vs. Allergy? (And Why You Need to Know)

You ate something "healthy"—but now you're bloated, uncomfortable, or foggy.
Was it a food sensitivity? An intolerance? A true allergy?

If you’re confused by the difference, you’re not alone.

Many people use these terms interchangeably—but they’re very different reactions, with very different health implications. And if you're trying to improve your digestion, energy, or overall wellness, understanding the difference is crucial.

Let’s break it down clearly and simply—so you can stop guessing, start identifying real triggers, and get your gut back on track.

Food Allergy vs. Food Intolerance vs. Food Sensitivity: What’s the Difference?

1. What Is a Food Allergy?

A food allergy is a serious immune response. When your body sees a specific food as a threat, it releases IgE antibodies, which can cause severe and even life-threatening symptoms.

Common signs of a food allergy:

• Hives, swelling, or itching

• Wheezing or difficulty breathing

• Anaphylaxis (a medical emergency)

• Rapid onset—usually within minutes

These must be diagnosed by an allergist with IgE testing or a skin prick test.

2. What Is a Food Intolerance?

A food intolerance happens when your body can’t properly digest or break down a certain food—not because of the immune system, but because of enzyme issues or poor gut function.

Common food intolerance symptoms:

• Bloating or gas

• Stomach cramps

• Diarrhea or loose stools

• Nausea

• Headaches

These typically show up within a few hours and are dose-dependent—you may tolerate small amounts but react to more.

Common culprits:

• Lactose (milk sugar)

• Fructose (fruit sugar)

• FODMAPs (fermentable carbs)

• Caffeine or alcohol

3. What Is a Food Sensitivity?

A food sensitivity is the trickiest—and most misunderstood—of the three.

It's often a delayed immune response, potentially involving IgG antibodies, that leads to chronic low-grade inflammation. The symptoms aren’t immediate, which makes it harder to pinpoint the source.

Common signs of food sensitivity:

• Brain fog

• Fatigue

• Joint pain

• Bloating or constipation

• Skin issues (acne, eczema)

• Mood changes or anxiety

These symptoms may show up hours or even days after eating the offending food—and they’re often cumulative.

How Gut Health and Food Sensitivities Are Connected

Your gut lining and microbiome play a big role in how your body tolerates (or doesn’t tolerate) food.

When your gut barrier is compromised—often called “leaky gut”—proteins from food can enter your bloodstream and trigger immune reactions, even if you're not truly allergic.

Over time, this can cause:

• Chronic inflammation

• Autoimmune flare-ups

• Worsening digestion and nutrient absorption

What Can You Do About It?

If you’re dealing with vague but persistent symptoms—fatigue, bloating, headaches, brain fog—it may be time to explore food triggers more deeply.

At OnPoint Nutrition, we use GI-MAP testing to uncover:

• Hidden gut infections

• Imbalances in beneficial bacteria

• Markers of inflammation, leaky gut, and digestion efficiency

We combine that with targeted elimination protocols and personalized guidance from a registered dietitian to help you feel like yourself again—without cutting out every food group forever.

Don’t Fall for These Common Myths

• “If I’m not allergic, it’s not a big deal.”
  Even mild sensitivities can disrupt your energy, digestion, and mood.

• “Food sensitivity tests are always accurate.”
  At-home IgG tests are not the full picture. A dietitian can interpret results in context with your symptoms and gut health.

• “Gluten and dairy are always the problem.”
  They might be—but for many people, it’s actually additives, poor gut health, or inconsistent eating habits.

Want help uncovering your food triggers?

If you're constantly asking yourself “What’s making me feel off?”, it might be time to stop guessing—and start investigating.

Understanding the difference between an allergy, intolerance, and sensitivity can be the missing piece between managing symptoms and actually solving the problem.

Check your insurance coverage and start working with a registered dietitian

You deserve real answers—and we’ll help you find them.