Can You Give Yourself a Food Intolerance?

Many of today's most popular diets call for the exclusion of certain food groups, often ones that are common allergens or subjects of food intolerance, like gluten and dairy. And while these eating styles and lifestyle choices can absolutely deliver amazing results both aesthetically and health-wise, the reality is that they're not always sustainable for everyone in the long-term. Think about it: If you go gluten- and dairy-free by choice, are you really willing to *never* eat regular pizza again?

If you are, that's awesome-keep doing your thing. Otherwise, you're probably going to indulge in some gluten- and dairy-laden treats once in a while, and you should feel free to do so. But what happens when you've skipped out on gluten and dairy for three months, then go ham on some pizza and ice cream? You might not feel so great afterward, and it's natural to think that you're intolerant of those foods. Here's what's really going on.

The Intolerance Hype

Food intolerance is very real when diagnosed by a doctor or dietitian through blood, skin, or breath tests, and avoiding foods you can't tolerate is obviously a good idea. That said, food intolerances are a little overhyped right now, particularly when it comes to gluten and dairy.

"There has been a marked increase in people with food intolerances (or claiming to have food intolerances) in the recent years," notes Alix Turoff, R.D., C.D.N., C.P.T., a dietitian and personal trainer based in NYC. "While it seems that food intolerances on the rise, it's hard to tell if that's because they're truly increasing or if it's because people are misinterpreting certain symptoms that might be the cause of something else." For example, bloating can be caused by a whole host of things like stress, birth control, and inadequate water intake, but it's easy to chalk it up to a food intolerance.

Plus, there's a misconception floating around that cutting out certain types of food is a "health-conscious" thing to do, regardless of whether you're truly intolerant of them. "In my opinion, if you're cutting out gluten and dairy, it should only be for either ethical reasons (like a vegan who is passionate about animal rights), or for digestive reasons (you're intolerant), but not for overall health reasons," says Turoff. Otherwise, you're not really doing yourself any health favors. "Foods that contain gluten have so much more fiber than their gluten-free counterparts, and foods like Greek yogurt are loaded with protein and are much better than many dairy-free options."

Overall, Turoff's advice is to not cut anything out completely unless you *really* need to. "Weight loss and optimal health can absolutely be achieved by leaving these foods in the diet for the majority of the population," she says.

Will Cutting Out a Food Group Make You Intolerant?

Technically, no-not if you weren't intolerant of it before. Take dairy, for example. "Your body doesn't stop producing lactase (the enzyme that digests lactose) just because you've taken it out of your diet," Turoff explains. "Theoretically, if you remove dairy from your diet, then add it back in, you should still be able to digest it." But that's not always the case in practice. "Many people find that when they cut certain foods out of their diet for a certain amount of time and add them back in, they experience digestive distress," she says.

Scientists think it may have something to do with your gut microbiome. "Your diet can alter the bacteria in your gut," Turoff says. "Cutting out gluten or dairy may play a role in the bacteria population in your gut, which may be the reason that digesting these foods becomes difficult after cutting them out." The same goes for vegetarians or vegans reintroducing fish and meat.

So while you're not going to make yourself truly intolerant of a food, it's not unexpected to have a harder time digesting it when your first add it back into your diet.

On the flip side, some dietitians have seen that removing a food group you're intolerant of (read: not allergic to!) and reintroducing it can actually make things better. "Reducing your exposure to a food that you have an intolerance to can actually make you better able to tolerate that food," says Melissa Groves, R.D.N., an integrative dietitian based in Portsmouth, NH. "Most of my clients are able to go back to eating foods they're sensitive to after avoiding them for a three- to six-month period and healing their gut." The only exception? We tend to make less lactase as we age, Groves says, so over time, some people become less and less tolerant of dairy. For people who are actually intolerant, removing it and adding it back in probably won't have the desired effect.

Another reason for potential discomfort after reintroducing foods like gluten and dairy? The fact that eating indulgent food can sometimes make you feel crappy, regardless of what's in it. "Most people don't think much about how they feel if they're used to eating a higher fat, processed foods diet," says Anne Danahy, R.D.N., a dietitian based in Scottsdale, AZ. "It becomes the norm. When they eliminate junk, they suddenly feel amazing for the first time, and when they go back to that processed food, the difference in how they feel becomes more apparent."

How to Reintroduce a Food the Right Way

Start slow. "The gastrointestinal (GI) tract really doesn't like change because the gut flora and digestive enzymes secreted are to some degree crafted by the foods we consume regularly," says Lisa Davis, Ph.D., PA-C, C.N.S., chief nutrition officer at Terra's Kitchen. "The good news is that it is not a permanent condition; the GI tract can and will adapt." Still, eating a whole pizza may cause digestive distress, so it's best to ease your way into it, she says.

While there's no magic number of how many times you need to eat something before you'll be back to normal, Davis emphasizes that variety is key in the beginning. "Although the gut adapts pretty well, to prevent major digestive distress, it's best to rotate throughout your diet every few weeks to keep the gut enzymes and bacteria diverse." That means trying to eat foods you're reintroducing perhaps just once or twice a week rather than every day.

Serving size is also key. "Keep portion sizes quite small and notice (or log) how you feel after eating," says Anna Mason, R.D.N., a dietitian based in Los Angeles. "If you're doing well with the small portion size, you can increase the portion size a bit and reevaluate." And when in doubt, check in with a dietitian. "Everyone is different, so having an educated, trained, and evidenced-based expert to guide you through lifestyle changes is never a bad idea."