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 healthcare 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. Many children with autism experience significant digestive problems, including diarrhea, constipation, and bloating.

"GAPS" is an acronym for "gut and psychology syndrome." The GAPS diet was developed by Natasha Campbell-McBride, MD, a physician and author 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.

The GAPS diet eliminates all grains, sugars, and simple starches and 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."

The 2021 U.S. News and World Report Best Diets ranks the GAPS diet number 37 in Best Diets Overall and gives it an overall score of 1.9/5.

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 person 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 tricky to follow since the diet relies on animal-based protein.

However, the diet is naturally 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, she says.

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 up to 1 1/2 hours to simmer.

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 (e.g., wheat, rice, barley, oats, and corn) and grain products (e.g., bread, breakfast cereal, and pasta)

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

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

  • Added sugar

  • 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—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: They must be very ripe. 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. As a result, the dairy-based foods allowed on the GAPS diet are almost all 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 natural and artificial sweeteners (and on ingredients such as maple syrup, molasses, and aspartame) means you'll need to steer clear of foods with added sugars.

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.

Sample Shopping List

The GAPS diet eliminates all grains and legumes and emphasizes animal protein, homemade bone broth, non-starchy vegetables, and fermented foods. The following sample shopping list provides suggestions for getting started with this eating plan. Note that this list is not all-inclusive and there may be other foods that work better for you.

  • Leafy greens (bok choy, collard greens, kale, green leaf lettuce, spinach)
  • Non-starchy vegetables (asparagus, Brussels sprouts, broccoli, cabbage, cauliflower, avocados, cucumbers, green beans, okra, zucchini)
  • Fruits (berries, oranges, pineapple, banana, grapefruit, raisins)
  • Meat and poultry (lean cuts of beef, ground beef, whole chicken, chicken breast, turkey breast)
  • Fish (salmon, halibut, cod, tuna, mackerel, sea bass)
  • Fermented dairy products (yogurt, kefir, ghee)
  • Fermented vegetables (pickled sauerkraut, kimchi)
  • Nuts (almonds, cashews, hazelnuts, pistachios, walnuts)
  • Nut butters (almond, cashew, hazlenut)
  • Nut flours (almond flour/meal, hazelnut flour/meal)
  • Olive oil, coconut oil
  • Butter
  • Honey
  • Fresh herbs (thyme, rosemary)
  • Eggs

Sample Meal Plan

A key tenet of the GAPS diet is making all or most of your own meals from scratch, including nourishing bone broths and fruit juices. The following three-day meal plan provides suggestions for what to eat on the GAPS protocol. Note that this plan is not all-inclusive, and if you choose to follow this diet there may be other foods that are more appropriate for your tastes and preferences.

Day 1

Day 2

Day 3

Pros and Cons

Pros
  • Encourages healthy home-cooked meals

  • May help some people

  • Strong online community for support

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

Online Community

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.

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 sauces, are allowed. This means you will spend a lot of time in the kitchen, which your lifestyle may or may not allow.

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 MyPlate 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.

A Word From Verywell

Autism, ADHD, and related mental health disorders can be challenging to manage, and it's understandable that parents of children with these conditions would want to do whatever they can to help. However, the GAPS diet requires a significant, ongoing commitment with no guarantee of success. If you're considering the GAPS diet for yourself or your child, 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, 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.
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  6. GAPS Diet. U.S. News & World Report Best Diets. 2021.

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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.