5 Signs You Could Have a Food Intolerance

Just like weight loss and fat loss, food intolerance and food allergy kind of sound like the same thing. But that's not quite the case.

Although they're often used interchangeably, food intolerances and food allergies are different. An allergy is your immune system reacting to and fighting off an ingredient that it mistakes as being harmful, according to the Cleveland Clinic.

Food intolerances are much more common. A food intolerance is a response from your digestive system when you eat or drink something your body can't break down. While food intolerances can be painful and uncomfortable, they're not potentially life-threatening like food allergies can be.

Now that we've cleared that up, read on to learn the common signs of a food intolerance and what you can do about it.

Excess bloating and gas are among the most common symptoms of a food intolerance, according to Niket Sonpal, MD, a New York City-based internist and gastroenterologist.

After a big, high-fiber meal, a little bloating and gas is common. But when these symptoms become uncomfortable or painful and happen every time you eat a certain food, they may hint at a food intolerance.

Although it's not the case for everyone, bloating and gas are often signs of lactose intolerance, or the inability to fully digest the sugar (lactose) in cow's milk products, Dr. Sonpal says. (Lactose intolerance is the the most common type of intolerance, he notes.)

If lactose intolerance is the cause of your bloating, you may also experience stomach pain or diarrhea a few hours after eating or drinking dairy products like milk, yogurt, cheese and ice cream.

Usually accompanied by (or the result of) too much bloating and gas, stomach pain is another typical sign of an intolerance, Dr. Sonpal says.

Stomach pain varies from person to person, but when it's caused by an intolerance, it usually feels like a cramping in the middle and lower abdomen.

When your body can't digest or break down certain foods, diarrhea is a typical side effect, Dr. Sonpal says. That's why it's a common sign that you might be sensitive to a food you recently ate.

"If you are having diarrhea frequently after eating, you might have impaired digestive function to certain foods," he says. "Lactose or gluten could be likely culprits, but those are not the only ones."

Although it may sound surprising, headaches are another sign of food intolerance, according to the Cleveland Clinic. And in severe cases, food intolerances can even trigger migraines.

Immunoglobulin G (IgG) antibodies are the most common type of antibodies in your blood. When you eat something your body sees as a threat, it releases these antibodies into the bloodstream, Dr. Sonpal says. Although it's not the case for everyone, sometimes, IgG antibodies can result in migraines and headache.

Ever eat something and feel super sluggish or tired right after? While a blood sugar crash may be to blame, sometimes a foggy, tired feeling may be a sign of a food intolerance.

When you eat foods your body can't process, your adrenal glands produce cortisol (a stress hormone) to help fight and reduce irritation and inflammation, Dr. Sonpal says. "This may cause fatigue if your adrenal glands are regularly producing cortisol to fight the body's inflammatory response," he adds.

An intolerance to lactose (a type of sugar found in dairy products) is the most common type of intolerance, according to the Cleveland Clinic.

"With lactose intolerance, depending on your level of sensitivity, you may need to either eliminate or reduce your intake of foods that contain lactose," says Bonnie Taub-Dix, RD, author of ​​​Read It Before You Eat It: Taking You from Label to Table.​

Although dairy products are loaded with vitamins and minerals, you can still reap these benefits while avoiding lactose by choosing fortified milk alternatives like almond milk.

Gluten is a protein found in wheat, rye and barley and these grains' derivatives. Although a gluten intolerance isn't quite the same as celiac disease (an immune reaction to gluten), your digestive system still may experience inflammation and unrest when you eat these grains.

As with gluten or lactose, some people may experience food intolerance symptoms when they eat eggs, especially if the yolk is intact, according to the Cleveland Clinic.

Although a nut intolerance or sensitivity usually isn't as severe as a nut allergy, it can still cause a lot of digestive discomfort.

Suspect you might have a food intolerance? The next steps you take depends on the symptoms you're experiencing, Dr. Sonpal says. If your symptoms are extremely painful or get in the way of completing your day-to-day tasks, it's best to see your doctor as soon as possible.

But if your symptoms are manageable, you can try to find the culprit on your own with a short-term elimination diet, he says. Here's how to do it:

1. Make a list of the foods you ate before you experienced symptoms.
2. Then, cut out one of these foods for about two weeks and monitor your symptoms. For example, if you ate yogurt topped with a nutty granola, the culprit could be dairy or nuts. Rather than cutting them both from your diet, try avoiding dairy for two weeks but continuing to eat nuts, and see if your symptoms continue. (Make sure to read food labels because some packaged foods may contain dairy without you realizing it.)
3. If you're still experiencing symptoms while avoiding that food, it's likely that food wasn't causing the issue. At the end of the two weeks, add that food or food group back into your diet and try cutting out a different food, to see if that's causing the issue. Continue this process until you've found the culprit.
4. If you notice your symptoms have reduced over the two-week period, gradually add that food back into your diet and pay attention to your body. If you feel the symptoms come back, then you should cut that food out and consult a dietitian who can help you craft a safe meal plan.