If you think that a certain food is making you miserable, you’re likely to jump to the conclusion that you’re allergic. Research published in the Journal of the American Medical Association
shows that as many as one-third of people are quick to assume that they suffer from a food allergy while, in reality, only about four percent of American adults have them. “A lot of people self-diagnose themselves,” says Lemond, “but allergies aren’t as common as sensitivities and the two conditions are very different from one another.”
So what’s the diff? A lot actually. For starters, an allergic reaction is swift and dramatic, and caused by an immune system response. When your body mistakes a food ingredient as harmful, it launches a defense system that releases IgE (immunoglobulin E) antibodies and chemicals like histamines in order to fight it. Symptoms typically develop quickly and are easy to detect, ranging from itching and rashes to hives, swelling of the mouth, lips, tongue or eyelids, or even anaphylaxis, a serious event in which the airways constrict.
Food sensitivities, on the other hand, are a lot sneakier and more difficult to detect, but typically aren’t as dangerous. Caused by your digestive system, they occur when your body is unable to digest or absorb certain foods or food components, usually due to a lack of an enzyme that is needed to break food down, such as a deficiency in lactase (the enzyme needed to break down lactose) in people who are lactose intolerant.
Generally, you need to consume a large quantity of the offending food before you begin to feel the effects. Food intolerances can be confusing and difficult to diagnose because of this very reason, since it may be difficult to tie the cramps and bloating you have today to the blue cheese in your salad from yesterday. Additionally, because the general state of your gut varies from day to day—influenced by factors such as gut flora, stress, and even the amount of sleep you’ve had—eating a certain food may give you a whopping stomachache one day and no symptoms the next, which makes it even more complicated to identify the intolerance and get to the bottom of what’s hindering your training.