What Is the GAPS Diet?

What Is the GAPS Diet?

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There’s a lot of excitement around the GAPS diet, an elimination diet that proponents claim may help contribute to healthier brain function. But there’s just as much caution and controversy, as research is scant within this new area of study.

The GAPS diet food list is extraordinarily restrictive — you’re not allowed any sugar, grains, soy, certain kinds of dairy, starchy vegetables, or processed foods. So if you’re considering an elimination diet like the GAPS protocol, you should talk to a medical professional first.

“Any elimination diet should be practiced under the care of a professional to ensure nutrition needs are being met, and to make sure the diet is appropriate for each individual’s unique needs and health concerns,” says Erin Judge, RDN, a specialist in IBS and digestive health disorders.

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The GAPS Diet Explained

“GAPS” stands for “gut and psychology syndrome,” and is based on the theory that your gut may influence your physical and mental health. This is a concept that is very new to the medical community, but is also gaining a lot of attention.

The GAPS diet was created by Dr. Natasha Campbell-McBride, MD. She asserts that poor nutrition can possibly create an imbalance of microbes in your gut. According to Campbell-McBride, this potential imbalance may cause a wide variety of psychological, neurological, and behavioral issues.

A leaky gut can release harmful bacteria and toxins into the bloodstream. According to Dr. Campbell-McBride’s theory, they then travel to the brain and compromise cognitive function. She argues this can cause and/or perpetuate everything from digestive and immune issues, to psychological disorders such as autism, ADHD, OCD, epilepsy, schizophrenia, and depression.


Is there a connection between diet and autism?

A number of researchers have declared a relationship between gut microbiota and autism, with some concluding that gut health may at least influence the severity of ASD symptoms.

In 2016 a study published in the World Journal of Pediatrics looked at children diagnosed with autism spectrum disorder (ASD) and found 54 percent had gastrointestinal abnormalities. That same year, a case study of a boy with ASD found his abdominal pains were significantly improved, as were certain autistic core symptoms, after taking probiotics for four months.

“The idea here is to reduce the difficulty digesting, concentrate on the healing, and let the gut start repairing first. Once that happens, the detox works better and the symptoms of other problems start to reduce,” says Inna Lukyanovsky, PharmD, functional medicine practitioner and author of Digestive Reset.

Whether that actually works is up for debate: A large study in July 2019 published in Frontiers in Psychiatry found that the GI symptoms experienced by people with autism aren’t associated with or fixed by fluctuations in certain macro- or micronutrients. As for any links beyond correlation, “there is currently no research to support ‘leaky gut’ as a cause for autism,” Judge says.


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Is the GAPS Diet Effective?

The ideas underlying the GAPS diet may have some merit when it comes to mood disorders and neurological diseases, according to Maggie Berghoff, a functional medicine nurse practitioner (FNP) based in Fort Wayne, Indiana. On a basic level, when a microbiome isn’t properly balanced, the body isn’t able to break down and absorb valuable nutrients from the foods or supplements consumed. “This leads to deficiencies in minerals and nutrients that are essential for all pathways of the body to function fully,” she says.

There is research to support the theory that diets such as GAPS may potentially help to improve symptoms in a wide array of conditions. Folks who ate high amounts of sugar were more likely to develop depression or anxiety over five years, according to research in Scientific Reports. A 2017 study in BMC Medicine even found that people who were clinically depressed felt significantly better after eating a modified Mediterranean diet for 12 weeks.

But none of that research specifically regards the GAPS diet. “While Dr. Campbell-McBride has seen much success with the protocol [in her practice], there are no peer-reviewed studies on the GAPS diet,” Judge says.

That means all we really have supporting this protocol is anecdotal evidence, and even that isn’t conclusive. “Many people can have great results following a GAPS diet, and others see no improvement in symptoms,” says Berghoff.

That said, the medical community is slowly learning more about how the gut may be linked to our overall health. “We do refer to the gut as our ‘second brain’ because of its role in hormone balance, communication throughout the body, and gene expression,” Judge notes.


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How Does the GAPS Diet Work?

The GAPS Diet follows the cadence of most any elimination diet. You cut all grains, sugar, soy, pasteurized dairy, starchy vegetables, and processed foods, and then reintroduce them slowly to see what irritates you. Uniquely, though, the GAPS diet calls for abstaining from all offending foods for 1½ to 2 years, and requires 6 months of normal digestion before you can start reintroducing (some of) them.

Introduction phase

A recommended precursor to the actual diet, the introduction phase is highly restrictive, but GAPS proponents claim that it’s intended to deliver quick benefits to your GI health. This phase can last anywhere from a few weeks to one year.

The introduction phase consists of six stages, each of which introduces different foods.

Stage 1: Homemade bone broth; boiled meat or fish; well-cooked vegetables; probiotics (i.e., fermented vegetable juices, yogurt, kefir, homemade fermented whey); ginger or chamomile tea with raw honey; purified water.

Stage 2: Add raw, organic egg yolks; casseroles made with meats and vegetables; fermented fish; homemade ghee.

Stage 3: Add avocado; sauerkraut and fermented vegetables; GAPS pancakes; scrambled eggs made with ghee, goose fat, or duck fat; probiotic supplements.

Stage 4: Add roasted or grilled meats; cold-pressed olive oil; freshly pressed carrot juice; GAPS milkshake; GAPS bread.

Stage 5: Add cooked apple purée; raw vegetables, such as lettuce and peeled cucumber; pressed fruit juice.

Stage 6: Add raw fruit; increase honey; baked goods sweetened with dried fruit.


Maintenance phase: Full GAPS diet

After your doc agrees that you’ve completed the introduction phase, you move into the full GAPS diet. This stage typically lasts 1½ to 2 years and doesn’t allow grains, sugars, starchy vegetables, refined carbohydrates, or processed foods.

The full GAPS diet consists primarily of the following:

  • Organic eggs
  • Fresh meat (preferably hormone-free and grass-fed)
  • Fish and shellfish
  • Fresh vegetables and fruit
  • Garlic
  • Natural fats (lard, tallow, lamb fat, duck fat, raw butter, olive oil, coconut oil, and ghee)
  • A moderate amount of nuts
  • GAPS baked goods made using nut flour

Other highly suggested guidelines include:

  • Consuming the organic versions of foods as often as possible
  • Avoiding all processed and packaged foods
  • Eating fruit between — not during — meals, and not in combination with meat
  • Combining meats with vegetables
  • Eat animal fats, coconut oil, or olive oil at every meal
  • Eat fermented food with every meal
  • Drink bone broth with every meal

Reintroduction phase

After at least 6 months of normal digestion, people can move onto the reintroduction phase which, just as it sounds, involves slowly returning certain foods to your diet over the course of several months and seeing how your body reacts.

Start with potatoes and fermented grains in small portions. If you don’t feel any digestive issues over two to three days, you can gradually increase the amount of food. Continue this process with starchy vegetables, grains, and beans.

Once you’ve completed the entire diet, continue to avoid refined, highly processed foods.


What Foods Can You Eat on the GAPS Diet?

Depending on the given phase of the GAPS diet, approved foods include:

protein foods- gaps diet


  • Eggs
  • Meat, including goose, lamb, pork, pigeon, pheasant, and poultry
  • Fish (fresh, frozen, or canned)
  • Fresh nuts (unsalted and unroasted)
  • White navy beans
  • Lentils
  • Lima beans

cheese and dairy- gaps diet


  • Cheese (brie, camembert, blue cheese, havarti, swiss)
  • Homemade yogurt

produce- gaps diet


  • Certain fruits (like apples, pears, kiwi, peaches, and pineapples)
  • Certain vegetables (including broccoli, kale, carrots, brussels sprouts, and zucchini)
  • Tomatoes (including puree and juice, without any additives apart from salt),


  • Ghee
  • Nut butters and oils

Cooking, condiments

  • Garlic
  • Nut flours
  • Pickles (without sugar)
  • Herbs (fresh or dried)
  • Honey

juice- gaps diet


  • Tea (must be weak and freshly made, never instant)
  • Freshly-pressed juices from permitted fruit
  • Wine (red or white but must be dry)
  • Gin, vodka, or scotch (occasionally)


Foods to Be Avoided on the GAPS Diet

In addition to all processed foods, grains, pasteurized dairy, sugars, and soy, you should avoid:

  • Cooking oils
  • Coffee and instant tea
  • Canned vegetables and fruit
  • Certain vegetables like okra, parsnips, white potatoes, sweet potatoes, and yams
  • Certain cheeses like feta, gruyere, and ricotta, as well as anything processed or spreadable
  • Cottage cheese
  • Certain beans like chickpeas, fava, black-eyed peas, butter beans, and cannellini
  • Condiments like ketchup
  • Processed, preserved, smoked, or salted meats
  • Milk alternatives (soy, rice, coconut)


Supplements Recommended by the GAPS Diet

Proponents of the GAPS diet recommend a regime of various supplements, namely probiotics, essential fatty acids, digestive enzymes, and cod liver oil. You’ll want to consult a doctor before embarking on any cycle of supplements.



These live microorganisms are intended to help replenish the beneficial bacteria in your gut. You’re advised to choose one that contains at least 8 billion bacteria cells per gram and multiple strains from different bacteria, including Lactobacilli, Bifidobacteria and Bacillus subtilis.

Note: The probiotic industry is growing fast, and there’s a lot of mixed opinion about the benefits of these supplements. There are also a lot of variables regarding the types of probiotics you purchase, with some being very pricey and not currently backed by science.

fish oil- gaps diet

Essential fatty acids: Fish oil, cod liver oil

Current research suggests that fatty acids may be linked to brain health and cognition, the GAPS diet advises taking fish oil and cod liver oil to get a supply of omega-3s and omega-6s. Also suggested: Taking a small amount of cold-pressed nut and seed oil blend.

Digestive enzymes

Dr. Campbell-McBride believes people with GAPS conditions experience low stomach acid production. So she suggests they take digestive enzymes — specifically betaine HCI with added pepsin — before each meal. HCI mimics hydrochloric acid, one of the main acids produced in the stomach, while pepsin, also produced in the stomach, helps to break down and digest proteins.


Are There Risks Associated With the GAPS Diet?

The major risk associated with the GAPS protocol is undernutrition, says Judge. “Any diet that’s highly restrictive for a long period of time will increase the risk of deficiencies.”

Plus, cutting grains and limiting vegetables could actually have an effect opposite of the intended one: “We know a low-fiber diet can decrease beneficial bacteria in the gut in as little as 24 hours. Restricting carbohydrates, which are our main source of fiber, can actually increase the risk for dysbiosis in the gut,” says Judge.

Indeed, Lukyanovsky agrees that some people simply may need more carbs, especially endurance athletes and those who engage in high intensity interval training.

Most importantly, don’t try the diet alone, but enlist the help of a dietitian or doctor, Judge says. And since the GAPS diet can take two full years to complete — which isn’t realistic or sustainable for most people — she adds that a trained professional can also help you find a protocol that is suitable for your lifestyle.

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