The GAPS diet is a type of elimination diet that focuses on healing the gut and promoting overall gut health. The premise of the diet is that a number of health conditions, particularly digestive disorders and neurodivergent conditions such as autism and attention deficit hyperactivity disorder (ADHD), can be caused by what is scientifically known as intestinal hyperpermeability, also known as leaky gut. The GAPS diet claims that healing leaky gut can improve or cure these conditions.
However, there is a lack of research and scientific evidence to support the GAPS diet. Let’s take a deep dive into what the GAPS diet claims to cover, how to follow it, what you can and can’t eat, and the benefits and risks of the GAPS diet guidelines.
What is the GAPS diet?
GAPS stands for Gut and Psychology Syndrome, a term coined by Natasha Campbell-McBride, who has degrees in medicine, neurology, and nutrition, to describe the connections between the digestive system and the brain. Campbell-McBride created the GAPS diet in 2004 after researching the relationship between food, nutrition, gut, and brain health while seeking answers for her own child, who was diagnosed with learning disabilities. She has since added Gut and Physiology Syndrome (still GAPS) to Gut and Psychology Syndrome, which focuses on the potential role of the gut in certain chronic physical conditions.
According to the GAPS diet website, GAPS theorizes that many health problems are rooted in an unhealthy gut, and that if one’s gut were to heal, then various digestive, neurological, and autoimmune disorders could also be resolved. These claims are made in reference to conditions such as autoimmune disorders, including celiac disease, Crohn’s disease, and rheumatoid arthritis; food allergies and intolerances; thyroid disorders; and other digestive disorders such as irritable bowel syndrome (IBS). Neurological and psychiatric conditions such as autism, ADHD, schizophrenia, and bipolar disorder are also included in the GAPS diet claims.
It is important to note that there are no peer-reviewed scientific studies examining the effectiveness of the GAPS diet. Most of the success stories are anecdotal and come from Campbell-McBride’s books and from her clinic in the United Kingdom.
What can you eat on the GAPS diet?
Introduction to Diet
There are three phases of the GAPS diet: Introduction, Full GAPS, and Reintroduction. There is also a dairy introduction phase, which is explained in more detail in the books. For those who want to follow the diet, Campbell-McBride recommends buying the books, Bowel and psychology syndrome And Bowel and physiology syndrome, so you can follow each stage as recommended.
The introductory diet has six phases, with the goal of healing leaky gut before moving on to the full GAPS diet. The intestinal lining is made up of cells that are supposed to absorb water and nutrients and move them into the bloodstream. Think of this intestinal lining as a protective barrier. If there are holes or tears in this barrier, undigested food and toxic bacteria can enter the body, causing inflammation and digestive problems. This is called intestinal hyperpermeability or leaky gut.
The staple foods in the introduction phase include meat broths, soups, and fermented foods. The length of time you stay in each phase varies from three to five days or four to six weeks or longer. Once diarrhea or other severe digestive symptoms have subsided, you can move on to the next phase. Campbell-McBride says it’s important to introduce small amounts of foods slowly as you move through the phases to see what you can tolerate. The allowed foods in the six phases of the introduction diet are as follows:
Phase 1: Homemade meat or fish stock; homemade soups with meat or fish stock; probiotic dairy or vegetable based foods; ginger tea.
Stage 2: Continue eating from Phase 1. Add raw organic egg yolks; meat and vegetable stews or casseroles; homemade yogurt or kefir; sauerkraut or vegetable juice; fermented fish; homemade ghee.
Phase 3: Add ripe avocado; GAPS pancakes (recipe in the book); scrambled eggs with ghee, goose fat or duck fat; sauerkraut; fermented vegetables.
Phase 4: Gradually add roasted and grilled meats, cold-pressed olive oil, freshly squeezed juices and baked bread with ground nuts or seeds.
Phase 5: Add cooked applesauce and raw vegetables, starting with lettuce and peeled cucumber. Avoid citrus.
Phase 6: Add a peeled, raw apple, and optionally other raw fruit and honey.
Full GAPS Diet
The full GAPS diet introduces more foods that are focused on healing and repairing the gut, Campbell-McBride says. She recommends people follow the full GAPS diet for 18 months to two years. On the diet, about 85 percent of the foods you consume each day should come from:
- Meat
- Fish
- Broth
- Eggs
- Fermented foods
- Vegetables
Fruit is also OK, along with baked goods made with nut or seed flour. See below for a more comprehensive list of foods you can and can’t eat.
Reintroduction phase
After six months of normal digestion and bowel movements, you can begin the reintroduction phase. During this time, you can slowly and gradually add foods back into your diet to see how you tolerate them. If you have no symptoms, you can increase the portions.
There is no exact order of foods to reintroduce; however, Campbell-McBride recommends starting with potatoes and fermented gluten-free grains. She also recommends that people following the GAPS diet continue to avoid highly processed foods and foods high in added sugars.
GAPS Diet Food List
For a comprehensive list of foods you can and cannot eat, please consult the GAPS website and books.
Foods You Can Eat on the GAPS Diet
- Eggs
- Meat
- stock
- Fish
- Shellfish
- Fresh vegetables
- Fruit
- Nuts
- Seeds
- Garlic
- Olive oil
Foods You Should Not Eat on the GAPS Diet
- Cereals
- Sugar
- Potatoes
- Parsnips
- Soy
- Commercial yogurt
- cottage cheese
- Rice
- Oats
- Coffee
- Corn
- Artificial sweeteners
- All processed foods in packages or cans
- Milk from any animal; soy milk, rice milk or canned coconut milk
Other GAPS Diet Recommendations
- Eat only fresh and frozen meat from high-quality sources, not canned, smoked or processed meat
- Eat only wild-caught, fresh or frozen fish
- Consume only cold-pressed, organic, raw vegetable oils
- Cook only with animal fat, coconut oil or ghee
- Do not heat food in the microwave
It is important to reiterate that there is little to no scientific support for the restrictiveness and specificity of this diet. Furthermore, meat and seafood can come from high-quality sources, even if they are canned, although the diet excludes canned foods (confused yet?).
Are there any benefits to the GAPS diet?
The GAPS diet emphasizes vegetables and fermented foods, both of which have been linked to gut health. Studies, such as a 2022 review in Micro organismssuggest that eating a variety of fruits and vegetables, olive oil, and oily fish can help maintain a healthy balance of bacteria in the gut, while a diet high in saturated fat and refined carbohydrates and low in fiber (also known as a traditional Western diet) can cause an imbalance of gut bacteria.
A review from 2022 in Nutrients suggests that fermented foods like kefir and sauerkraut, along with probiotic-rich foods like yogurt, can help improve gut flora. And limiting highly processed foods with added sugar, refined grains, and artificial sweeteners is also beneficial for overall health. Refined carbs and sugar can increase inflammation in the body, and some studies, such as a 2021 review in Limits in nutritionhave shown that consuming artificial sweeteners can alter gut bacteria.
Disadvantages of the GAPS Diet
There are no peer-reviewed clinical studies evaluating the GAPS diet or proving that it is effective in healing the gut and treating the conditions it claims to treat. Additionally, it is unclear whether leaky gut is the result of a particular condition and not the cause.
While scientists agree that leaky gut can occur, research has not shown that improving the intestinal barrier necessarily treats or improves specific conditions, according to a 2019 review published in the journal Intestine.
The GAPS diet is extremely restrictive, which has several consequences. For starters, it takes a lot of time to plan and cook meals. What’s even more concerning, however, is that the diet was originally developed to help children with behavioral and digestive issues. Putting children—or adults, for that matter—on an extremely restrictive diet can lead to malnutrition and/or disordered eating patterns. Additionally, highly restrictive plans are usually not enjoyable or sustainable for a long period of time, which negates the results they promise. Additionally, it appears to be gluten-free, as it does not allow grains.
It is extremely important to weigh the risks and benefits of the GAPS diet, especially because there is no substantial evidence that the diet provides health benefits and because it may be harmful.
Sample GAPS Diet Meal Plan
Breakfast
Scrambled eggs with zucchini, spinach, tomatoes and gorgonzola cheese
Lunch
Spinach salad with broccoli, carrots, tomatoes, chicken, avocado, walnuts and blue cheese
Homemade dressing with olive oil and apple cider vinegar
Dinner
Salmon with lemon and garlic and homemade tzatziki (Greek yogurt, lemon juice, cucumber, dill)
Roasted Brussels sprouts and pumpkin
It comes down to
So, should you try the GAPS diet? In my opinion, no. This dietitian does not recommend the GAPS diet as there is no research to support its claims or efficacy. Additionally, it is extremely restrictive, time-consuming, and relatively expensive. There are more effective, evidence-based ways to improve digestive and neurological conditions that involve small changes that are sustainable. We highly recommend working with a gastroenterologist who can diagnose your condition and a Registered Dietitian/Nutritionist (RDN) who specializes in that condition and can provide specific solutions tailored to your dietary preferences and lifestyle.