This super-restrictive eating plan claims to cure everything from autism to depression—but science doesn't back it up.
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You know the old saying, "you are what you eat"? Well, what if what you eat could have a direct impact on your mental health? This concept is still being widely studied, but an eating plan called the GAPS diet claims to treat many different psychiatric and psychological disorders, among other conditions—but is that legit?

What is the GAPS diet?

This diet, developed 15 years ago by Natasha Campbell-McBride, M.D. (who now practices as a nutritionist in the U.K.), aims to address "gut and psychology syndrome" or, yup, GAPS.

It was "derived from the Specific Carbohydrate Diet (SCD) created by Dr. Sidney Valentine Haas to naturally treat chronic inflammatory conditions in the digestive tract as a result of a damaged gut lining," according to Dr. Campbell-McBride's GAPS website.

Dr. Campbell-McBride's theory is that many conditions affecting your brain are caused by a leaky gut. This is a condition in which the lining of your intestine becomes more permeable, resulting in undigested food molecules escaping from your digestive tract. When these toxins and waste particles flow through your bloodstream, they cause your liver to work overtime, leading to inflammation throughout your body that's linked to all kinds of health concerns and diseases. Seems sound, right? Well, wait for it: In Dr. Campbell-McBride's book, she says the GAPS diet helped cure her child's autism.

The GAPS diet supposedly reverses all these issues by healing your gut through food, and is based on the concept of eliminating carbohydrates that are indigestible for some people, says Suzanne Dixon, R.D.N., M.P.H., a registered dietitian at The Mesothelioma Center in Orlando.

It might sound enticing in theory, but the eating plan isn't exactly easy to follow. In reality, it's a very strict elimination diet that rules out grains, pasteurized dairy, starchy vegetables, and refined carbohydrates.

What foods can you eat on the GAPS diet?

The GAPS diet has an introduction phase that's broken down into six stages, during which your food choices are pretty limited.

You move through the stages slowly, progressing to the next one once your body is tolerating the food in each stage. You'll know when you're tolerating food when you have a normal bowel movement, says Carolyn Dean, M.D., N.D., a speaker and author based in Hawaii. (If we're being honest, diarrhea supposedly kicks in when you start GAPS and it's no joke.)

In stage one, it's pretty much a given you're going to be hangry. You're eating (or rather, drinking) things like homemade bone broth (not store-bought), juices from probiotic foods and ginger; and sipping mint or chamomile tea with honey between meals (if you can call them "meals"). If you can tolerate dairy, then unpasteurized, homemade yogurt and kefir are allowed. This phase can last anywhere from three weeks to a full year, depending on your symptoms.

In stage two, you can eat raw organic egg yolks, ghee, and stews made with vegetables, meat, or fish.

In stage three, you add in avocado, fermented vegetables, GAPS-specific "pancakes" (there are various recipes out there, but many are made with a combination of coconut oil, almond butter, egg yolks, and cooked pumpkin or squash), and scrambled eggs cooked in ghee.

In stage four, you can reintroduce grilled and roasted meats, cold-pressed olive oil, vegetable juice, and homemade bread from a GAPS-approved recipe.

In stage five, cooked apple puree, raw vegetables (like lettuce and peeled cucumber), fruit juice, and small amounts of raw fruit (excluding citrus) are allowed.

In stage six, more fruit is introduced, including citrus.

Once you've successfully completed all six stages and are tolerating all these foods, you proceed to the full GAPS diet, says Dr. Dean. This can last for anywhere between one to two years. During that time, you'll be mainly eating hormone-free and grass-fed meats, animal fats (like lard and ghee), fish, shellfish, organic eggs, fermented foods, and vegetables. Small amounts of nuts and GAPS diet recipes for baked goods made with nut flours are also allowed. (Here's the full GAPS diet food list.)

There are also some quirky rules to the full GAPS diet, like not eating meat and fruit together, and consuming bone broth as well as cold-pressed olive oil or coconut oil with every meal—which doesn't exactly make going out for dinner with friends easy. Not to mention, you're also avoiding all refined carbs and packaged and canned foods for the duration of the diet.

Does the GAPS diet claims have any merit?

So, if you think you have leaky gut and are making a major commitment to following the GAPS diet, what's the potential payoff? Dr. Campbell-McBride claims it's a natural cure for everything from autism, depression, and dyslexia to schizophrenia, bipolar disorder, and more.

It's true that there's increasing evidence that your gut microbiome and brain are linked—but it's still unclear exactly how. That said, the GAPS diet does seem pretty far-fetched, and the lack of science proving any of these things is a major concern among health professionals.

"There are no studies that have examined the effects of the GAPS dietary protocol on the symptoms and behaviors associated with autism, [nor any] examining the effect on any of the other conditions it claims to treat, as far as I know," says Dr. Dean. "It's impossible to know how it could help people with [these conditions]."

Other experts are concerned about the name itself since the meaning of GAPS isn't widely known. "Just the word 'gaps' implies there is something wrong with your diet," says Dixon. A gap implies something is missing. "It also implies a 'quick fix' can work—simply address these gaps and you'll feel better."

Still, it's not surprising that there's increasing buzz about the diet. As more and more people are talking about their struggles with anxiety, depression, and other mental health challenges, it's making everyone more mindful of their mental well-being, says Dixon. "If a diet can fix how you're feeling, that's pretty enticing," she admits.

It's important to note that the GAPS diet is not intended as a weight-loss diet, though that can be a side effect since you're cutting out processed foods and carbohydrates. (More: Why an Elimination Diet Won't Help You Lose Weight)

The Bottom Line

With a diet this strict, you really should be under the direct supervision of a registered dietitian, says Dixon—and especially so for children, who are at a high risk of malnutrition on such a restricted eating plan. She notes that while diet alone is very unlikely to cure complex brain disorders, it may be worth a try for certain autoimmune disorders like IBD, for which medications often have unpleasant side effects. However, "full scale-implementation of GAPS is not something I'd endorse," she says. (Related: Changing My Diet Helped Me Get My Life Back After Being Diagnosed with Ulcerative Colitis)

Dr. Dean says that while overall the diet is very healthy once you get through the six initial stages, she doesn't recommend it as a cure for any behavioral or digestive issues without solid research behind to back it up.

"Some parts of it—such as whole foods, limited carbs, and no processed foods—will likely aid in decreasing inflammation, but not due to the specific layout and diet plan itself," says Dr. Dean. "The whole point is to include foods that feel good and discontinue foods that don't, but unless you're cooking for yourself all the time, it's very difficult to maintain."