The Gut and Psychology Syndrome (GAPS) diet is an elimination diet that is claimed to help treat autism and other behavioral and psychological conditions. Although some aspects of the GAPS diet show promising results, more research is needed to validate that all components of the GAPS diet are necessary for the benefits it claims. People should therefore proceed with caution.
What is the GAPS Diet?
The GAPS diet follows the premise that gut health is linked with overall physical and mental health. In this theory, improving gut health can improve other health conditions. It was created to improve gut health. The idea is that improving gut health might lessen inflammation that may contribute to certain neurodevelopmental conditions.
Dr. Natasha Campbell-McBride, who invented the GAPS diet, believes that poor nutrition and a leaky gut, or increased intestinal permeability, are responsible for many psychological, neurological, and behavioral issues. The term “GAPS” stands for “gut and psychology syndrome.” According to the GAPS theory, a leaky gut-a term used to describe an increase in the permeability of the gut wall-allows chemicals and bacteria to enter your bloodstream, causing a host of health consequences ranging from “brain fog” to autism.
At the core of the GAPS diet, people avoid foods that are difficult to digest and might damage the gut flora or gut lining. They replace them with nutrient-rich foods that help the gut heal. According to the GAPS theory, a leaky gut releases harmful bacteria and toxins into the bloodstream, which then travel to the brain and interfere with the brain functioning. The theory says that eliminating foods that damage the gut could help treat conditions such as autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD), and dyslexia.
Conditions the GAPS Diet Claims to Help
Dr. Campbell-McBride originally designed the GAPS diet with the aim of treating her son’s autism. Some people also use the GAPS diet as an alternative therapy for a range of psychological and behavioral conditions, including:
Read also: Starting the GAPS Diet
- Autism
- ADHD
- Dyslexia
- Dyspraxia
- Epilepsy
- Depression
- Schizophrenia
- Bipolar disorder
- Obsessive-compulsive disorder (OCD)
- Disordered eating
- Childhood food intolerance and allergies
Dr. Campbell-McBride’s initial aim with the GAPS diet was to help children with behavioral and mood disorders. However, some adults now use it to improve digestive problems.
Does the GAPS Diet Work?
To date, there is no research to support that the GAPS diet can help treat the conditions it claims to. The diet has not been scientifically tested, and the only claims in support of this diet are anecdotal.
Although current research suggests that there is a connection between the brain and the gut, particularly for conditions such as anxiety and depression, research is mixed on certain aspects of the diet. While there are many testimonials of improvement, there is limited published evidence to suggest that following all components of the GAPS diet is required to improve psychological or behavioral conditions.
Most experts agree that there is no cure for ASD. It is possible, however, to improve health conditions associated with ASD, such as gastrointestinal (GI) problems. One 2014 systematic review found that children with ASD had significantly higher rates of GI symptoms than those without. The authors say that children with ASD were more prone to abdominal pain, constipation, and diarrhea. Some research suggests these symptoms are linked to unbalanced gut microbiota or dysbiosis.
One case study reported that a 12-year-old boy with ASD and celiac disease showed significant reductions in GI symptoms and core autism symptoms after 4 weeks of probiotic treatment. Findings from a 2014 study that tested 133 children found no association between intestinal permeability and the presence of ASD symptoms. On the contrary, a 2010 pediatric study found different results.
Read also: The Hoxsey Diet
Nearly thirty-seven percent of patients with ASD and twenty-one percent of their first-degree relatives showed altered intestinal permeability (IPT) suggesting a hereditary factor. Patients with ASD on a gluten and casein free diet had lower IPT levels than those who ate unrestricted. The authors conclude that a gluten-free diet could benefit a subgroup of patients with ASD.
Another case study of a 5 year old boy had significant improvement in GI symptoms, development and cognition when his undiagnosed celiac disease was diagnosed and treated with a gluten-free diet. The authors suggest that all children with neurodevelopmental delays be screened for malabsorptive conditions and nutritional deficiencies that could heavily influence cognition.
Autoimmune conditions have also been associated with ASD and a study published in Nutritional Neuroscience found a significant number of autism patients had elevated antibodies simultaneously to gliadin protein present in gluten-containing foods and cerebellar cortex neurons.
More research is needed to elucidate what other dietary changes may be effective to substantially affect ASD.
Stages of the GAPS Diet
The diet is restrictive and may take up to 2 years to complete. Following the GAPS diet can be a very lengthy process.
Read also: Walnut Keto Guide
There are three stages to the GAPS diet:
- The introduction diet
- The full GAPS diet
- The reintroduction phase
1. The Introduction Diet
Dr. Campbell-McBride recommends that many people follow the introduction diet before starting the full GAPS diet. While highly restrictive, this phase aims to heal the gut and reduce digestive symptoms quickly. It can last anywhere from a few weeks to 1 year. This is the most restrictive part of the diet. It is called the “gut healing phase”.
The introduction diet has six progressive stages. Each stage introduces new foods but foods within each stage are individualized to each person based on tolerance. People should not progress to the next stage if they experience digestive symptoms, which may include:
- Diarrhea
- Bloating
- Gas
- Constipation
- Abdominal pain
Stage 1
In stage 1, the diet consists of:
- Homemade meat stock
- Boiled meat or fish
- Well-cooked vegetables
- Probiotics, such as fermented vegetable juices, yogurt or kefir, and homemade fermented whey
- Ginger or chamomile tea with raw honey
- Purified water
Stage 2
In stage 2, add the following foods:
- Raw, organic egg yolks
- Casseroles made with meats and vegetables
- Fermented fish
- Homemade ghee
Stage 3
In stage 3, add the following foods:
- Avocado
- Sauerkraut and fermented vegetables
- GAPS pancakes
- Scrambled eggs made with ghee, goose fat, or duck fat
- Probiotic supplements
Stage 4
In stage 4, add the following foods:
- Roasted or grilled meats
- Cold-pressed olive oil
- Freshly pressed carrot juice
- GAPS milkshake
- GAPS bread
Stage 5
In stage 5, add the following foods:
- Cooked apple purée
- Raw vegetables, such as lettuce and peeled cucumber
- Pressed fruit juice
Stage 6
In stage 6, add the following foods:
- Raw, peeled apple
- Raw fruit
- Increase honey
- Baked goods sweetened with dried fruit
After completing the introduction diet, many people move onto the full GAPS diet. The GAPS diet recommends that you move from one phase to the next once you can tolerate the foods you have introduced.
2. The Full GAPS Diet
During the GAPS diet, avoid all grains, sugars, starchy vegetables, refined carbohydrates, and processed foods. This stage lasts 18-24 months but is individualized and may require less time for some. People are instructed to follow this diet for a long time, often 1 to 2 years. Some people are instructed to follow this diet for life, depending on the condition they’re trying to treat.
Acceptable GAPS foods include:
- Eggs
- Meat, fish, and shellfish (fresh or frozen only)
- Fresh vegetables and fruit
- Garlic
- Natural fats, such as olive oil, coconut oil, and ghee
- A moderate amount of nuts
- GAPS baked goods made using nut flour
The GAPS diet also recommends that people:
- Use organic food as often as possible
- Avoid all processed and packaged foods
- Eat fermented food with every meal
- Drink bone broth with every meal
- Avoid eating fruit with meals
- Combine all protein food with vegetables, which the theory says will keep body acidity levels normal
The heavy emphasis on fats and protein can lead to lower fiber intake. Fiber is important for many reasons. Eating too much meat at the expense of fiber-rich foods could also raise your risk of colorectal cancer.
3. The Reintroduction Phase
After at least 6 months of normal digestion, people can choose to move on to the reintroduction phase. The GAPS diet suggests that the reintroduction phase may begin after you have experienced normal digestion and bowel movements for at least six months.
The final stage of the GAPS diet involves gradually reintroducing food items over the course of several months. The diet doesn’t detail the order of reintroduction or the exact foods you should reintroduce.
The diet recommends starting with potatoes and fermented grains. Start with small portions and gradually increase the amount of food, as long as no digestive issues arise. Continue this process with starchy vegetables, grains, and beans. It’s recommended to wait until you’ve had normal digestion and stools for at least 6 months before starting reintroduction. The GAPS diet doesn’t give precise instructions for which foods to introduce first. But it’s advised to reintroduce foods one at a time and add new foods every 2 to 3 days.
After completing the GAPS diet, many people continue to avoid refined, highly processed foods. It’s also recommended to continue to avoid ultra-processed foods and refined sugars.
Foods to Avoid on the GAPS Diet
Foods to avoid on the GAPS diet include:
- Sugar and artificial sweeteners
- Syrups
- Alcohol, but adults can have a glass of dry wine occasionally
- Processed and packaged foods
- Grains such as rice, corn, wheat, and oats
- Starchy vegetables, such as potatoes and yams
- Milk
- Beans, except white and green beans
- Coffee
- Strong teas
- Soy
- Commercial dairy, aside from hard cheese
Sample Meal Plan
Here is a sample meal plan for the GAPS diet:
- Start the day with one of the following:
- A glass of filtered lemon water and kefir
- A glass of freshly pressed fruit and vegetable juice
- For breakfast:
- GAPS pancakes topped with butter or honey
- One cup of lemon and ginger tea
- For lunch:
- Meat or fish with vegetables
- One cup of homemade meat stock
- One serving of probiotics, such as kimchi, sauerkraut, yogurt, or kefir
- For dinner:
- Homemade vegetable soup made with meat stock
- One serving of probiotics, such as kimchi, sauerkraut, yogurt, or kefir
Potential Benefits of the GAPS Diet
There is no evidence to suggest that all components of the GAPS diet can help treat the conditions it claims to. The current research doesn’t offer any convincing evidence that it’s effective.
Following this diet could, however, improve a person’s gut health. It encourages people to eat fewer processed foods and more fruits, vegetables, and natural fats. These simple dietary changes could improve gut health and overall health.
Even though there’s no clear evidence that the GAPS diet treats certain conditions, it may still have some health benefits. Some of the dietary changes associated with the GAPS diet protocol may help to:
- Lower diabetes risk: People who stop eating refined carbohydrates and processed foods have a lower risk of obesity and Type 2 diabetes.
- Improve gut health: Your digestive system needs good bacteria to function smoothly. The GAPS diet includes fermented foods that help boost this kind of healthy bacteria.
- Lower chemical exposure: The GAPS diet recommends avoiding artificial sweeteners, pesticides, and preservatives. Researchers are still trying to understand how these chemicals may be harmful to your body.
- Limit alcohol consumption: The GAPS diet mostly gets rid of alcohol.
Improving Gut Health
The GAPS diet could improve gut health in three main ways:
- Eliminating artificial sweeteners: According to some animal studies, artificial sweeteners can create imbalances in gut bacteria and increase the risk of metabolic problems.
- Focusing on fruits and vegetables: A 2016 study involving 122 people showed that eating fruits and vegetables can prevent a potentially harmful strain of bacteria from growing in the gut.
- Including probiotics: Probiotics contain many beneficial bacteria. One study suggests that eating probiotic yogurt may help lower blood sugar levels among people with metabolic syndrome.
Possibly Managing Some Psychological and Behavioral Conditions
According to a review study, recent clinical studies have suggested that microbes in the gut can significantly affect brain function. The researchers suggest that gut imbalances could contribute to schizophrenia and other complex behavioral conditions. Findings from a 2019 systematic review suggest that probiotics have strong therapeutic potential for treating depressive symptoms.
Risks and Considerations
GAPS diet guidelines do not explicitly account for all nutritional needs. When following this diet, people should make sure that they are getting enough vitamins and minerals to avoid developing nutritional deficiencies. The restrictive nature of the GAPS diet also makes malnutrition a real concern. Many people have food aversions and sensitivities - especially children with autism or other behavioral conditions. If their only choices are GAPS-approved foods, they may not eat enough. This could lead to malnutrition if they don’t eat enough calories or nutrients.
Also, the diet can be hard to follow and has some health risks.
Some of the ways it can be harmful include:
- Time and stress: People whose children have disabilities or medical conditions are already under a higher amount of stress than other families. The added stress of having to prepare special foods might not be manageable in the long term.
- Food poisoning: The GAPS diet incorporates raw and unpasteurized dairy products. Pasteurization kills bacteria that can cause serious illness. The diet also recommends raw eggs, which can also lead to serious bacterial infections.
- Disordered eating: The GAPS diet has a long list of rules to follow. And in some people, it could lead to disordered eating or orthorexia, an unhealthy focus on eating only “healthy” foods. When people become so focused on their diet that they forget about other important parts of life, their mental health can suffer.
- Lower fiber intake: The heavy emphasis on fats and protein can lead to lower fiber intake. Fiber is important for many reasons. Eating too much meat at the expense of fiber-rich foods could also raise your risk of colorectal cancer.