Skip to content
Join Life Time
an illustration of foods that cause health issues (bread, eggs, tomatoes, cheese, peanut)

Over the past eight years of working at Life Time, I have coached thousands of clients, many of which who have also completed a food sensitivity lab test. Often people complete this testing in an effort to inform their weight-loss journey, pinpoint their personal trigger foods, or minimize their digestive symptoms or other symptoms associated with food sensitivities such as headaches, skin issues, joint paint, congestion, and more. While all those things can be accomplished by identifying food sensitivities, the secret is not the test itself — it’s putting in the work to heal your digestive tract and improve the foundation of your metabolism after you learn your results.

I repeatedly see how knowing one’s individual food sensitivities can alter their nutrition plan to be more customized and better help them reach their goals. While an elimination diet can also be a great starting point, many people need to see it written in black and white to have the motivation to really stick to removing certain foods from their diet.

Even though there are parts of the food sensitivity test that are straightforward, there are also many questions surrounding the reasons for doing the test and the ways it can positively inform and impact your health that often surprise people. Here are answers to the questions I hear most often from clients.

What’s the difference between a food allergy, food intolerance, and food sensitivity?

While you may hear “allergy,” “intolerance,” and “sensitivity” used interchangeably in conversation, they are all quite different reactions in the body, and their distinctions are important to know as you pursue lab testing.

A food allergy is when someone has a severe and immediate reaction to consuming a particular food. For example, you may think of someone who has a peanut allergy going into anaphylaxis after eating one of the nuts and needing to visit the hospital.

A food intolerance is when someone cannot physically breakdown the food they are consuming. One popular example you may think of is lactose intolerance. In this instance, symptoms typically quickly appear as significant digestive upset.

Then there are food sensitivities. In my opinion, these are the most difficult to pinpoint. Food sensitivity symptoms can develop right after you eat a food, hours later, or even days following. Symptoms can also vary greatly from person to person. The variability in timing and display of symptoms is often why many may not realize they have a food sensitivity.

What are some symptoms of a food sensitivity?

As you can imagine, I often have clients who are surprised to learn they have food sensitivities, with them only finding out once they test. The cardinal symptoms associated with food sensitivities are often digestive health issues, such as bloating, gas, heartburn, constipation, or diarrhea, and therefore are often misinterpreted as “normal.” However, fatigue, excess body fat, poor sleep, headaches, sinus congestion, skin issues, and so much more can all be suggestive of underlying food sensitivities.

What are some common food sensitivities?

When it comes to food sensitivities, everyone is unique, which is why at Life Time we test for 108 different foods so we can really customize the approach and pinpoint what your issue foods are. The ones we test for include:

Gluten-Containing Grains
Wheat flour, barley flour, gluten, spelt flour, rye flour, oat bran

Gluten-Free Grains
Amaranth, buckwheat flour, corn, millet, quinoa, rice

Lentil, soybean, pea, bean mix (white, string, kidney), chickpea

Apple, orange, date, apricot, banana, cherry, grape mix (blue, white, raisin), grapefruit, kiwi, lemon, nectarine, plum, pineapple, pear, peach, strawberry, watermelon

Nuts & Seeds
Pistachio, cashew nut, walnut, peanut, almond, coconut, flax seeds, hazelnut, poppy seeds, sunflower seeds, sesame

Mushroom mix 2 (bay bolete, cep), red cabbage, asparagus, turnip cabbage, carrot, bell pepper, zucchini, eggplant, tomato, potato, artichoke, beetroot, broccoli, corn salad, celery, cucumber, leek mix (leek, chive), lettuce mix (butterhead, iceberg), mushroom mix 1, onion mix (onion, shallot), olive, sweet potato, spinach

Dairy & Egg
Egg yolk (chicken), yogurt, cow’s milk, egg white (chicken), goat’s milk/goat’s cheese, sheep’s milk/sheep’s cheese

Beef, chicken, lamb meat, pork, turkey

Fish & Seafood
Anchovy, crayfish, codfish, shrimp-prawn mix 1, sole, salmon, swordfish, tuna, trout, venus clam

Herbs & Spices
Horseradish, mustard seeds, vanilla, garlic, rosemary, basil, chili, cinnamon, mint mix (peppermint, mint), nutmeg, oregano, parsley, pepper (black/white), thyme

Black tea, cocoa bean, coffee, honey, yeast mix (baker’s brewer’s )

That being said, there are some foods I see come up more often than others. What I see people reacting to most often is gluten, cow dairy, and eggs. While that’s not surprising to a lot of people, like I mentioned before, seeing it in writing is often needed to help motivate people to eliminate (even if just temporarily) those favorite food groups.

Pinpointing which of these common food sensitivities you may be reactive to is important, as it can help dictate any elimination diet work we may want to do, as well as inform a more individualized (and successful) nutrition plan. Because gluten and dairy are the most common sensitivities, it’s often where I have my clients begin in an elimination diet. We typically see great results from removal as these foods can cause a lot of inflammation in the body.

Why might I have food sensitivities?

Many times the “why” isn’t initially considered by individuals, but the reality is, addressing food sensitivities isn’t as simple as solely removing the foods that you react to — it’s essential to figure out the root cause.

The reason people develop food sensitivities is because their digestive tract is not as strong and healthy as it needs to be, and there could be several reasons for that. The number one reason I see is stress on the body, whether that stress is a result of work, family life, poor diet, intense exercise, inflammation, nutrient deficiency, or some combination of them all. This stress can affect the permeability of your gut lining and in turn lead to food sensitivities.

What can I do about any food sensitivities I may have?

Addressing food sensitivities is a three-part process: Removing the foods based on your lab results for a certain length of time, healing the gut, and then reintroducing the foods.

The most common misstep I see people make is either not addressing the root cause or not working to heal the gut. This may mean that while you’ve removed the foods that you’re also using specialized supplementation, focusing on improving your sleep, or working on your stress management. Not neglecting these steps will set you up for the most success when you reintroduce the foods.

Once you enter the reintroduction phase, you’ll reintroduce foods one at a time, noticing to see if any symptoms arise. If they do, it’s an indication that it’s a food you’ll want to leave out of your diet for longer or potentially long term. If no symptoms appear, you can feel good about including that food in your plan. That is the good news: Food sensitivities can often just be temporary!

It’s common for people to see a vast improvement in how they feel when they remove their food sensitivities from their diet. I cannot tell you how many times I get on the phone and someone will say, “my trainer told me to do that,” but they didn’t actually take the steps. It often takes getting the test and having the results in front of you to feel encouraged enough to really alter your diet.

What does the gut have to do with food sensitivities?

Your gut health is the foundation of your metabolism. When your digestive tract is off, it can affect nearly everything with your body. You’ve likely heard the phrase “you are what you eat,” but in all reality, you actually are what you eat, breakdown, absorb, and metabolize.

The digestive system is complex. It’s important that each step is working well to help support a healthy nutrient status, levels of inflammation, cholesterol clearance, and hormone health. A healthy gut is also a key component for solid immunity.

Wrapping Up

Food sensitivities have become an extremely popular conversation, but remember, if you want to feel better and improve your health, there’s more to the process then just cutting out the foods you react to.

Testing can be a helpful starting point, but we must also uncover the root issue that led to the food sensitivities in the first place and, most importantly, do the work to heal the gut and sustain gut-supportive habits moving forward.

Learn more about Life Time’s food sensitivity test. If you do the work and are still not seeing success, you may want to consider digging in even deeper and working one-on-one with one of our registered dietitians.

Keep the conversation going.

Leave a comment, ask a question, or see what others are talking about in the Life Time Health Facebook group.

Katie Knafla, RD, LD

Katie Knafla, RD, LD is the assistant program manager for lab testing at Life Time.

Thoughts to share?

More From Life Time

At-home food sensitivity test collection box.

Food Sensitivity Test

Optimizing gut health is about more than just improving digestion: it’s tied to energy levels, inflammation, joint pain, immune health, headaches, and hormones. Arm yourself with information about what your body needs with an at-home food sensitivity test.

Shop Food Sensitivity Test


More Like This

bowls of different foods and Samantha McKinney smiling photo

Allergies, Sensitivities, Intolerances: All About Food Reactions

With Samantha McKinney, RD
Season 6, Episode 19

Adverse reactions to many foods are on the rise, and while allergies are often more easily identifiable, sensitivities and intolerances typically are not. Regardless, they can all cause troubling effects in the body. Samantha McKinney, RD, explains the differences between food allergies, sensitivities, and intolerances, what the common food offenders are, how to spot signs of a reaction, and —  in the case of the latter two — why those signs are often symptoms but not the root cause.

Listen >
Headshot of Samantha McKinney.

Taking Care of Your Gut: Why It’s Critical to Health + How to Do It

With Samantha McKinney, RD
Season 2, Episode 3

The gut is often considered the gatekeeper to our overall health — and imbalances many times surface in surprising ways. Samantha McKinney, RD, discusses its far-reaching impacts and shares daily lifestyle strategies we can use to support our gut health.

Listen >
Back To Top