How Hidden Food Sensitivities Are Holding You Back
Most athletes understand that food is fuel. Some athletes understand that in order to have good quality performance you need good quality fuel. But what not a lot of athletes realizes is that food sensitivities (which are different from food allergies) are a real thing and they can impact your performance.
Let’s take a closer look at what exactly food sensitive are, how they are secretly holding you back, and how to find out what they are (spoiler alert: it’s not by doing a blood test, check out this podcast episode to learn why I don’t like blood testing for food sensitivities).
how food Sensitivities impact athletes
Keep in mind that athletes may be more likely to suffer from food sensitivities because training (especially high intensity and endurance training) causes stress to the immune system and makes your gut leaky.  So not only will your body react to foods that cause inflammation more when you are exercising heavily, but it will also cause more stress on your immune system. 
Food sensitivities and intolerances can cause increased inflammation and increase the overall stress load on the body, both of which result in an increased need for recovery time. They compromise your gut function making your body less able to absorb nutrients from your food (which also increases your recovery time). Because your immune system is “distracted” when you eat foods that you are sensitive to, constantly eating these foods makes you more likely to get sick, especially after a hard workout. This is because your immune system is busy fighting things that shouldn’t be in your blood stream (incompletely digested proteins from foods that entered because your gut is leaky) but don’t pose and immediate threat, that it doesn’t have the resources to devote to fully fighting off infections.
Food sensitivities also can cause weight gain or inability to lose weight due to cortisol dysregulation and they can impact your respiratory system due to the inflammation caused by constantly exposing yourself to foods that you have an intolerance to.
Fueling yourself is not all about just eating healthy foods. It’s incredibly important to know what foods are best for YOUR body. Because while something like broccoli is considered to be healthy, if you have a sensitivity to broccoli and eating broccoli triggers your immune system or causes you to feel bloated, then it’s not serving you well and you should avoid it.
It’s also important to keep in mind a few things about bloating and digestive symptoms. Some people experience bloating as the “I just stuffed a basketball under my shirt” look. But in my experience, most people aren’t even aware they are bloated and they just feel that they have a few pounds that they need to lose. This can sometimes make it hard to distinguish which food are causing you problems if you don’t know what to look for. Also, you don’t have to experience obvious digestive symptoms to have food intolerances or leaky gut. If you have ever felt your performance has suffered and not really been sure why, or if you have symptoms such as fatigue, skin issues, joint pain, headaches, or slow recovery times, then you are probably experiencing the symptoms of food sensitivities.
As athletes, everything we do tends to focus around maximizing performance. Most of us pay attention to the food we eat specifically because we want to eat things that are going to help us perform better. If you have a food intolerance and you are eating those foods, your body is constantly on high alert and your immune system is being overworked and your body can’t focus on recovery, muscle repair, or performance.
allergy vs. intolerance vs. sensitivity
It’s important to understand that food sensitivities or intolerances are not the same as food allergies. Allergies can be life threatening situations and should be taken very seriously. Food intolerances cause a host of undesirable symptoms, but are not directly life threatening.
Allergies in general, but specifically food allergies are immediate reactions to a substance. They can be something minor like hives or a rash or they can be major and cause anaphylaxis or death if not treated immediately. Food allergies do not show up the first time a person is exposed to a food. It takes more than one exposure to develop an allergy and what starts as a minor allergy can turn into a life threatening one if you continue to expose yourself to the the substance you are allergic to.
Symptoms: Hives, shortness of breath, itchy mouth or throat, rash, swelling, nausea, vomiting.
Common triggers: Peanuts, dairy, shellfish, nuts (almonds, cashews, etc.)
When the body lacks the specific enzyme required to break down a particular food, this is called an intolerance. Dairy is probably the most common example of this. People who lack the enzyme lactase cannot break down dairy (lactose) and are thus lactose intolerant. Eating dairy is not life threatening to them because their immune system doesn’t react to it, but it typically causes digestive symptoms that can range from mild to incredibly unpleasant.
Food sensitivities often get lumped in with food intolerances, but they are different. A food sensitivity can occur immediately up to several days after eating a food and simply means that your body has a negative reaction to the food. A food sensitivity does not directly involve your immune system like a food allergy does. Non-celiac gluten sensitivity is probably the most commonly known food sensitivity. 
It’s also import to note that unlike a food allergy where the severity of the symptoms does not necessarily correlate with the amount of exposure  (if you’re allergic to peanuts and you have a little bit of peanut your reaction is the same as if you have a lot of peanuts), due to the inflammatory nature of food sensitivities, dose matters. So while you may not have an obvious reaction to one serving of a food, three servings might cause a noticeable reaction.
Food sensitivities can be hard to pinpoint because the reaction can be mild and it can occur up to several days after you’ve eating a food. Continual exposure to unknown food triggers can cause increased intestinal permeability (leaky gut), active the immune system, and cause chronic inflammation. Some common issues that have been liked to food sensitivities are:
Eczema, rashes, and other skin issues
Gas and bloating
IBS, constipation, and diarrhea
Prolonged workout recovery time
Recurrent illness or infections
how to uncover hidden food sensitivities
I mentioned before that I’m not a big fan of any of the blood testing options for uncovering food sensitivities. These tests are inaccurate and unreliable (I cover this topic in more depth a podcast episode, listen here). You could take the same test twice on the same day and get completely different results. You can also read this article from the American Academy of Allergy Asthma and Immunology why they don’t recommend these tests either.
Please note that for people who have food true allergies, traditional allergy testing is helpful.
So what are you supposed to do?
The gold standard for identification of food sensitivities is an elimination diet. This can be overwhelming and is definitely not the easiest way to determine what foods are causing you issues, but it will give you much better and more accurate information than a food sensitivity test will.
When done properly, you not only learn what foods you are sensitive to, but also how much of these foods you can tolerate. By systematically eliminating and reintroducing single foods or food groups, you can design a diet that is completely personalized to you and your needs. This means that because it is completely personalized to you that it will also be optimal for your athletic performance. The research shows that eliminating food sensitivities is extremely beneficial to your performance. 
The key to uncovering the most information about which foods are holding you back and which foods will maximize your performance is not in the elimination diet itself (though that part is important), but in the process of eliminating and reintroducing foods in a systematic way.
find your perfect diet
An elimination diet is simply the process of systematically eliminating and reintroducing foods. There are thousands of ways to go about this and it’s easy to get overwhelmed and bogged down by the details and then do nothing. I have created an entire course that walks you through the exact process I use with all of my clients and patients to determine what foods they should and shouldn’t be eating. Click here to learn more about the course.
Step 1: Eliminate problematic foods
The most common foods that are eliminated during an elimination diet are gluten, dairy, soy, corn, peanuts, and alcohol. But these are not the only foods that can cause problems. I teach a two phased approach where you eliminate the most common culprits during the first phase and then after one round of reintroducing foods, you go back and do a second round of more targeted eliminations if you feel that it’s necessary. My recommendations for a basic elimination diet are to eliminate the following foods:
Artificial food additives
Processed vegetable and seed oils
Sugar and artificial sweeteners (I also recommend limiting natural sweeteners like honey and maple syrup)
The recommended length of time that you need to eliminate potentially problematic foods varies. I’ve read everything from three weeks to six months. My recommendation is at least three weeks, but if you are suffering from a lot of symptoms or feeling really tired and run down, six to eight weeks is probably better. If you suffer from an autoimmune disease, you may need to eliminate foods for 6 months or more in order to eliminate your symptoms.
Step 2: Reintroduce eliminated foods
After you’ve eliminated these potentially problematic foods for about six weeks, you’ll need to follow a reintroduction schedule. You’ll test one food over a period of nine days (you can do this more quickly, but given that food sensitivity symptoms can take several days to develop, you run the risk of missing a reaction if you try and rush it).
During the reintroduction process you’ll need to pay close attention to what your body is telling you. You may not notice anything the first time you eat the food which is why it is important to reintroduce one food at a time. If you reintroduce two or more foods in the same period, you won’t know which food is causing the problem if there’s a problem.
Some symptoms to watch out for during the reintroduction process are:
Gastrointestinal symptoms: stomach ache, changes in bowel habits, heartburn, nausea, constipation, diarrhea, gas, bloating
Fatigue or low energy
Trouble falling asleep or staying asleep, not feeling rested in the morning
Headache or dizziness
Joint or muscle aches or pain
Skin changes: rash, acne, dry skin, small red bumps, eczema, dry hair, brittle nails
Mood issues: feeling depressed, low mood, decreased tolerance for stress, increased anxiety
Any symptoms that previously went away during elimination or any symptom that gets worse
Step 3: Explore other foods
Completing the previous two steps will allow you to bring some foods back into your diet before you take more out. The overall goal of this process isn’t more restriction, it’s to make sure that you are eating the foods that serve your body and your performance well, which is why I don’t encourage people to eliminate all the things in one go. It is very challenging to stick to such a restrictive diet and I have found that most people do better if they are able to bring in some of the foods they initially eliminated if they tolerate them.
Some other foods to explore are:
Nuts and seeds
Be sure to download my elimination and reintroduction guide by entering your email below. I’ll send you an easy to follow guide that covers:
The basics of an elimination diet and how to get started
How to reintroduce foods
How to track which foods are causing you problems
Other foods to explore if you’re still not feeling your best
If you want help getting started or you would like more guidance with this process, check out the Find Your Perfect Diet course here. I will teach you exactly how to create your own perfect diet so that you can have more energy and better performance!