What Is the GAPS Diet?

The gaps diet

Verywell / Debbie Burkhoff

At Verywell, we believe there is no one-size-fits-all approach to a healthy lifestyle. Successful eating plans need to be individualized and take the whole person into consideration. Prior to starting a new diet plan, consult with your health care provider or a registered dietitian, especially if you have an underlying health condition.

The GAPS diet is not a weight-loss diet, but rather, a restrictive diet intended for the natural treatment of autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), dyslexia, and other mental health conditions.

The diet eliminates all grains, sugars, and simple starches. Parents seeking alternative therapies for children who've been diagnosed with a mental health disorder may turn to this diet as a potential treatment.

"GAPS" is an acronym for "gut and psychology syndrome." The GAPS diet was developed by Natasha Campbell-McBride, MD, a physician with supplemental post-graduate degrees in neurology and nutrition. When her son was diagnosed with autism, she utilized her background to develop a potential treatment through nutrition.

In 2004, Dr. Campbell-McBride published her research in the book, "Gut And Psychology Syndrome," which details the science behind the brain-gut connection. She also describes a diet known as the "GAPS Nutritional Protocol," and claims it has been successful in treating patients with learning disabilities and other mental health conditions, including her child with autism.

Healing the gut, according to Dr. Campbell-McBride, also can help ease symptoms of some mental health conditions. Many children with autism experience significant digestive problems, including diarrhea, constipation, and bloating.

The GAPS diet is based on the Specific Carbohydrate Diet (SCD), which is used to treat celiac disease, Chron's disease, ulcerative colitis, and inflammatory bowel disease (IBD). Similarly, the GAPS diet relies on homemade broths and fermented vegetables to heal damage to the gut wall, often referred to as "leaky gut syndrome."

What Experts Say

"According to the GAPS diet, eliminating many foods allows the gut to “heal and seal.” There is little evidence to support these claims. Experts worry the numerous restrictions—including grains, most dairy, and starchy vegetables—increases the risk of nutrient deficiencies."

Chrissy Carroll, RD, MPH

What Can You Eat?

The GAPS diet begins with an introductory phase (with very limited food selection) followed by a full diet phase, which allows a wider variety of foods. Dr. Campbell-McBride urges everyone to try the introductory phase before moving on to the entire diet. However, she states that those whose conditions are particularly severe may need to stay in the introductory phase for longer.

The introductory phase allows only homemade meat, chicken, or fish stock; a homemade soup made with stock plus non-starchy vegetables; homemade fermented foods such as sauerkraut or vegetables; homemade fermented dairy products; organic egg yolks; and avocado.

Gradually, as digestive symptoms subside, you can add pancakes made from nut butter and vegetables; homemade ghee; fried eggs; roasted and grilled meats; olive oil; bread made with almond flour; cooked apple; raw vegetables; homemade juice; and raw apples.

Once the patient can eat all of those items without digestive symptoms, then they're ready for the full GAPS protocol. It takes at least one-and-a-half to two years on the GAPS diet protocol before those following the plan can begin to eat non-compliant foods again.

What You Need to Know

Dr. Campbell-McBride recommends that people hoping to achieve results from the GAPS diet start with the introductory phase and stay on it (working through its six stages) for as long as it takes for their digestive symptoms to subside. Once digestive symptoms have abated, she says they can move on to the full GAPS diet and add more foods.

"Your patient needs to have at least six months of normal digestion before you start introducing foods not allowed on the GAPS diet," she says. "Do not rush with this step." Some people may take longer than two years to be able to accommodate non-GAPS foods. The first foods to introduce once you're ready to come off the diet include new potatoes and fermented gluten-free grains.

Dr. Campbell-McBride urges those considering the GAPS diet to follow it strictly according to the blueprint in her book. That makes it difficult to modify. Vegetarians may find the diet is tricky to follow since the GAPS diet depends on animal-based protein.

However, the diet already is gluten-free, corn-free, and peanut-free, and easily can be made dairy-free if you have an allergy or an intolerance to dairy foods. Those with a tree nut allergy will need to avoid certain recipes, but shouldn't have much trouble finding foods they can eat on the diet.

Following the GAPS diet means you'll cook almost all your own food from scratch. In many cases, you'll use homemade meat or fish stock for soups, broths, and other recipes. Dr. Campbell-McBride believes that homemade stock has a "soothing effect" on areas of inflammation within the intestinal tract. Commercial stock products don't have this same effect, according to Dr. Camobell-McBride.

To make homemade meat or poultry stock, you'll need to start with bones and joints with a little meat on them. Place them in a large pan and fill the pan up with water. Add a bit of sea salt and a few herbs to taste, bring it to a boil, and then cover and simmer it on low heat for 2 1/2 to 3 1/2 hours. If you prefer, use a slow cooker and simmer the mixture on low overnight. To make homemade fish stock, use the entire fish or fish fins, and cook it for up to 1 1/2 hours.

What to Eat
  • Meat, poultry, fish, and eggs

  • Non-starchy vegetables

  • Most fruit

  • Fermented dairy (yogurt, kefir, and ghee)

  • Fermented fish (using GAPS recipe)

  • Fermented vegetables

  • Homemade vegetable and fruit juice

  • Nuts, nut butters, and nut flour

  • Butter

  • Olive oil

  • Coconut oil

  • Honey

What Not to Eat
  • All grains (wheat, rice, barley, oats, and corn) and everything made with them (bread, breakfast cereal, and pasta)

  • Starchy vegetables (potatoes, parsnips, yams, and sweet potatoes)

  • Quinoa, buckwheat, sorghum, millet (and other "gluten-free" grains

  • Sugar and anything that contains it

  • Maple syrup, molasses, corn syrup, and any other syrup

  • Aspartame in any form, and any food that contains it

  • Candy, cookies, cakes, and ice cream

  • Milk (unless it's fermented)

  • All processed foods

  • All alcoholic beverages

Here's a rundown of the foods that are allowed (and aren't allowed) on the GAPS diet protocol:

What to Eat

Meats, Poultry, and Fish

The GAPS diet protocol allows all types of animal protein. However, you'll need to cook them and serve them only with allowed sauces and spices, which means you'll be making them at home for the most part.

Non-Starchy Vegetables

Some vegetables are allowed, some are not. Non-starchy vegetables are encouraged on the GAPS diet, and in fact, you're urged to ferment them using recipes and cultures that are "GAPS-approved." Non-starchy vegetables include carrots, onions, asparagus, broccoli, cabbage, Brussels sprouts, cauliflower, kale, Swiss chard, lettuce, and beets.

Fruit

Virtually all fruits are allowed. Bananas are the only type of fruit that comes with a modification on the diet: try to eat only very ripe bananas. If they have brown spots on them, they're ready.

Fermented Foods

Foods that have been fermented also are recommended as a source of beneficial bacteria. Dr. Campbell-McBride's book includes recipes for sauerkraut, fermented vegetables, and fermented probiotic beverages.

What Not to Eat

Grains

These include multiple foods that are staples in most people's diets, including bread, cereal, crackers, pasta, cakes, cookies, and all other conventional baked goods. Dr. Campbell-McBride believes that these foods irritate the gut lining and ultimately damage it, which affects how nutrients are absorbed.

Dairy Products

Only fermented dairy products are allowed in most cases. Milk—particularly cow's milk—can irritate and damage the intestinal lining in much the same way as grains do, according to Dr. Campbell-McBride's theory. Fermented versions of dairy-based foods do not have this effect. Therefore, nearly the only dairy-based foods allowed on the GAPS diet are homemade fermented foods: yogurt, kefir, ghee, and whey. The exception is butter, which is allowed.

Dr. Campbell-McBride encourages fermented dairy and says you can add it beginning in the introductory phase of the diet.

Starchy Vegetables

Vegetables that are not allowed on the diet include potatoes, sweet potatoes, parsnips, and yams. Beans and legumes are also not allowed on the GAPS diet.

Sugar and Added Sugars

On the GAPs diet, sugar is considered harmful to the gut lining. The ban on sugar (and on ingredients such as maple syrup, molasses, and aspartame) means you'll need to steer clear of foods with added sugars, too.

Processed Foods and Alcohol

All processed foods (with the exception of the very few that are specifically labeled "GAPS-compliant") contain ingredients that are off-limits on the diet. In addition, alcoholic beverages are not allowed.

Pros and Cons

Pros
  • Encourages healthy home-cooked meals

  • May help some people

  • Strong online community

Cons
  • Little research showing it's effective

  • Very difficult to maintain

  • Eliminates multiple foods

Though the benefits of the GAPS diet have not been proven in clinical settings, it's possible you or your child may benefit from this eating plan. Take a look at the pros and cons as you weigh your decision about trying this diet.

Pros

Healthy Home-Cooked Meals

The GAPS diet encourages home-cooked meals made from fresh vegetables, fruits, meats, poultry, and fish. No junk food, fast food, or even restaurant-made food is allowed on the diet. This means the GAPS diet will be a healthier diet than the typical American diet.

May Help Treat Symptoms

Some proponents of the diet claim that it can help improve symptoms of autism, ADHD, and other mental health conditions in children and adults who follow it. Dr. Campbell-McBride maintains a list of physicians whom she has trained on the diet, though there is limited evidence to prove its efficacy.

Online Community

Finally, there's a strong online community that can help you start and continue the diet. Parents and others who have implemented the GAPS diet will answer questions, provide support, and often act as cheerleaders for those just beginning the diet.

Cons

Limited Evidence

Like other diet treatments for autism, the GAPS diet does not have any rigorous medical studies to back it up. Unfortunately, there's little scientific evidence to indicate that any of Dr. Campbell-McBride's recommendations—ranging from homemade broth to fermented foods—can help improve symptoms of autism or other mental health conditions.

May Cause Nutritional Deficiencies

Some medical professionals warn that cutting out so many healthy foods—such as whole grains and legumes—can lead to nutritional deficiencies in children and adults who adhere to the diet.

Restrictive and Time-Consuming

Because of its restrictive nature, the GAPS diet is extremely difficult to follow. You'll need to cook all your own food from scratch—no store-bought convenience foods, such as broth or most sauces, are allowed. This means you might spend a lot more time in the kitchen, which you may or may not have time for.

Is the GAPS Diet a Healthy Choice for You?

The U.S. Department of Agriculture (USDA) dietary guidelines recommend that around one-quarter of daily calories come from grain-based products, preferably whole grains. These include bread, cereal, pasta, rice, tortillas, and grits. Since the GAPS diet does not include any grains, it does not adhere to federal guidelines.

The USDA's ChooseMyPlate tool recommends that people get around one-half of their daily food allotment from fruits and vegetables. Here, the GAPS diet comes much closer to the USDA's nutritional advice.

As for protein-based foods, such as meat, poultry, fish, legumes, and nuts, the GAPS diet somewhat adheres to USDA recommendations, which call for around one-quarter of your daily calories to come from protein sources. However, the GAPS diet does not allow legumes, which are a great source of protein and fiber. Dairy products are allowed for most people on the GAPS diet, but fermented dairy (yogurt and kefir) is preferred. The USDA advises consuming dairy products with calcium daily.

Since the GAPS diet is designed to help treat symptoms of mental health conditions and is not intended for weight loss, it's important to make sure you're still getting enough calories on this restrictive eating plan. The USDA recommends consuming around 2,000 calories per day for weight management, but that number can vary based on a number of factors like age, sex, weight, and level of physical activity. Use this calculator tool to determine your daily calorie needs.

The GAPS diet aligns with the USDA's recommendations for fruits and vegetables, protein, and dairy. However, it restricts grains and many other healthy carbohydrates and starches. There is also little scientific evidence to prove that the diet can effectively treat autism and other mental health conditions.

Health Benefits

The diet itself claims to heal the gut by eliminating many foods considered to be problematic for those with mental health disorders, including grains and dairy, and by adding foods with natural probiotics. While many people attest that the diet has worked for them or for their child, there aren't any strong medical studies or other research to show its effectiveness.

Health Risks

Though there are no common risks associated with the GAPS diet, an eating plan that restricts healthy carbohydrates could lead to nutrient deficiencies and unintended weight loss. Additionally, some research has cautioned against the consumption of bone broths on the GAPS diet, since bones may contain heavy metals and present a risk for lead contamination.

Similar Diets

The GAPS diet shares similar traits with other restrictive grain-free diets, though there are some key differences. Here's how they compare:

Specific Carbohydrate Diet

The GAPS diet was developed from the Specific Carbohydrate Diet (SCD), and the two are quite similar: they both eliminate all grains and simple starches, and they both rely on fermented dairy products to restore balance in the intestinal lining.

Still, the GAPS diet is intended for children and adults with autism and other mental disorders, while the SCD targets people with inflammatory bowel disease (though some have used SCD to treat autism).

Gluten-Free, Casein-Free Diet

The gluten-free, casein-free (GF/CF) diet is the most common diet used by families for children with autism and related conditions. It eliminates all gluten (found in wheat, barley, and rye) and all casein (found in milk and milk-containing products). The theory behind the diet is that people with autism spectrum disorders have trouble digesting the gluten and casein proteins, which are similar in structure to each other.

Like the GF/CF diet, the GAPS diet eliminates gluten-containing foods (although it does allow dairy). But the GAPS diet also eliminates gluten-free grains such as rice and corn, while the gluten-free diet allows them.

A Word from Verywell

Autism, ADHD, and related mental health disorders can be challenging, and it's understandable that parents would want to do whatever they can to help their children. However, the GAPS diet requires a significant, ongoing commitment.

If you're considering the GAPS diet, make sure to speak with your doctor or your child's pediatrician to make certain it's the best choice for you and your family.

Remember, following a long-term or short-term diet may not be necessary for you and many diets out there simply don’t work, especially long-term. While we do not endorse fad diet trends or unsustainable weight loss methods, we present the facts so you can make an informed decision that works best for your nutritional needs, genetic blueprint, and budget, and goals.

If your goal is weight loss, remember that losing weight isn’t necessarily the same as being your healthiest self, and there are many other ways to pursue health. Exercise, sleep, and other lifestyle factors also play a major role in your overall health. The best diet is always the one that is balanced and fits your lifestyle.

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Article Sources
Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Doctor-Natasha.com. Who is Dr. Natasha?

  2. Campbell-McBride N. Gut and Psychology Syndrome: Natural Treatment for Autism, Dyspraxia, A.D.D., Dyslexia, A.D.H.D., Depression, Schizophrenia, 2nd Edition. United Kingdom: Medinform Publishing; 2018.

  3. Ristori MV, Quagliariello A, Reddel S, et al. Autism, gastrointestinal symptoms and modulation of gut microbiota by nutritional interventionsNutrients. 2019;11(11). doi:10.3390/nu11112812

  4. Braly K, Williamson N, Shaffer ML, et al. Nutritional adequacy of the specific carbohydrate diet in pediatric inflammatory bowel diseaseJ Pediatr Gastroenterol Nutr. 2017;65(5):533-538. doi:10.1097/MPG.0000000000001613

  5. Kakodkar S, Farooqui AJ, Mikolaitis SL, Mutlu EA. The specific carbohydrate diet for inflammatory bowel disease: a case seriesJ Acad Nutr Diet. 2015;115(8):1226-1232. doi:10.1016/j.jand.2015.04.016

  6. U.S. Department of Health and Human Services and U.S. Department of Agriculture. 2015–2020 Dietary Guidelines for Americans. 8th Edition. December 2015.

  7. Monro JA, Leon R, Puri BK. The risk of lead contamination in bone broth dietsMed Hypotheses. 2013;80(4):389-390. doi:10.1016/j.mehy.2012.12.026

  8. Barnhill K, Devlin M, Moreno HT, et al. Brief report: implementation of a specific carbohydrate diet for a child with autism spectrum disorder and fragile x syndromeJ Autism Dev Disord. 2020;50(5):1800-1808. doi:10.1007/s10803-018-3704-9

  9. Children’s Minnesota. Gluten-Free, Casein-Free Diet for Autism Spectrum Disorder.

Additional Reading
  • Campbell-McBride, Natasha. Gut and Psychology Syndrome: Natural Treatment for Autism, Dyspraxia, A.D.D., Dyslexia, A.D.H.D., Depression, Schizophrenia. Medinform Pub., 2010.