The GAPS diet has been proposed as a treatment for conditions including autism, schizophrenia, depression, and ADHD. But is there evidence to support the use of this extreme protocol?
The Gut and Psychology Syndrome (GAPS) was proposed by Dr. Natasha Campbell-McBride, a medical doctor with a specialty in neurology. McBride believes that many neurological and psychological conditions, including autism, ADHD, dyslexia, depression, schizophrenia, obsessive-compulsive disorder and many others, are actually due to problems in the gut.
Broadly speaking, McBride’s theory is that intestinal permeability allows toxins to escape through the lining of the intestinal tract and into the bloodstream, where they travel to the brain and impair function. McBride has developed a dietary protocol which is intended to heal the gut, thereby clearing the toxins from the brain and restoring normal function. McBride claims to have cured her own child of autism using this protocol.
What is the GAPS diet?
The GAPS diet protocol begins with an elimination phase that lasts up a year. It is extremely restrictive and starts out with bone broth, fermented vegetable juice, and herbal tea.Very gradually, you introduce small amounts of other foods, including egg yolks, meat, cooked vegetables, small amounts of fruit and nut flours. But your diet consists primarily of bone broth, meat, and vegetables.
After completing the elimination phase, you enter the maintenance phase. Your diet consists of the GAPS protocol-approved foods introduced in phase one and you continue to avoid refined carbohydrates, preservatives, and artificial colorings. This phase continues for another one to two years.
Finally, during the reintroduction phase, you are allowed to reintroduce some starchy carbohydrates such as potatoes and whole grains, but you continue to avoid all processed foods and refined carbohydrates
Obviously, you’d have to be intensely motivated to follow a regime this restrictive for this long.
Obviously, you’d have to be intensely motivated to follow a regime this restrictive for this long. Which is why the GAPS diet generally only appeals to people (or the parents of people) suffering from severe symptoms. You’d have be pretty desperate to sign on for something like this. But if it works, might if be worth it?
What’s the Evidence?
Unfortunately, there are no studies to support the effectiveness of this regime, only anecdotal reports, starting with McBride’s claim to have cured her own child’s autism. But anecdotal reports are notoriously unreliable. For one thing, there are always a lot of uncontrolled variables that make it hard to say whether the observed effect was really due to the proposed cause.
But don’t a whole lot of positive anecdotal reports start to add up to plausible evidence? Not necessarily. As science nerds like to say, the plural of anecdote is not data.
For one thing, people who have a positive result are much more likely to share that result than people who don’t get any benefit. This is called “reporting bias” and it tends to make positive outcomes seem much more likely than they actually are.
Leaky Gut or Leaky Theory?
Even if the protocol does bring some relief, the leaky gut explanation doesn’t hold much water. A few weeks ago, dietitian and digestive specialist Tamara Frueman was on the podcast to talk about intestinal permeability and the so-called leaky gut syndrome.
As Tamara explained, even if there is some degree of intestinal permeability, that does not mean that toxins or undigested food particles are being are released into the bloodstream, much less transported to the brain. That’s simply not how the gut (or the bloodstream) works.
Pros and Cons of the GAPS Diet
People who actually manage to adhere to this protocol may, in fact, perceive some benefits. But it may have to do with entirely different mechanisms than the ones proposed by McBride.
A very limited diet can help to calm an irritated gut and a carefully executed elimination diet can help identify foods to which you are have a negative reaction. However, these protocols can be implemented over the course of weeks and months, not years.
Even when there are no specific food intolerances, simply reducing or removing caffeine, alcohol, highly processed foods, refined carbohydrates and/or added sugars could help someone feel a lot better.
Given the extreme restrictiveness and long duration of the GAPS diet, there’s also a very real possibility of serious nutrient shortfalls.
To the extent that the GAPS diet produces positive results, these benefits could likely be achieved with a far less punishing regime. Given the extreme restrictiveness and long duration of the GAPS diet, there’s also a very real possibility of serious nutrient shortfalls.
Is the GAPS Diet Good for Autistic Kids
Using this protocol with an autistic child presents additional challenges. As autism advocate Jamianne Verkade points out, children with autism frequently have limited diets already due to sensory processing issues that make them extremely sensitive to and intolerant of a lot of textures, smells, and tastes. Autistic kids also often struggle with any change in their routine.
“Introducing a new food is usually incredibly difficult for an autistic child,” Verkade says, “let alone completely derailing a familiar eating routine and replacing it with something brand new. This makes the child all the more susceptible to malnutrition as they are likely to reject new foods (at least at first) and are not ideal candidates to sustain such a restrictive diet long-term.”
Before we put these kids and their families through such an ordeal, it’s worth at least trying a less extreme approach.
Before we put these kids and their families through such an ordeal, it’s worth at least trying a less extreme approach. One study, for example, found that eliminating gluten and casein-containing foods (such as wheat and dairy), led to improvements in function for some kids diagnosed with autism spectrum disorder. Although a gluten-free, casein-free diet is no easy lift, it’s a heck of a lot less restrictive than the GAPS diet.
Although dietary interventions sometimes reduce outward manifestations of autism, that does not necessarily mean that the person is less autistic. Verkade points out that autistic people frequently have poor digestive health. (Whether this is cause or effect is not yet known.)
“Many of the most recognizable autistic traits are much more obvious when an autistic person is under stress or unwell,” Verkade says.
“When neurotypical people become stressed or sick, their coping mechanisms are much more widely recognized and accepted by the general public. They might be cranky or snippy, things that we recognize as a 'normal' response to stress and chronic sickness.
“When an autistic person is stressed or chronically ill, they might find comfort in repeating certain phrases over and over, stimming with hand flapping, or be much more easily overwhelmed by their surroundings due to sensory overload. When an autistic person is feeling well, it may not be so obvious that they are autistic because they don’t need to resort to these 'regulators'.
“I would imagine this could be true of people with other conditions the GAPS diet claims to treat. When your body is healthy, you have way more mental, emotional, and physical resources to manage your mental health.”
The Bottom Line on the GAPS Diet
There is clearly an intimate two-way connection between our guts and our brains. An unhealthy gut can increase stress and anxiety, for example. Psychological treatment for stress or depression can often lead to improvements in functional GI diseases. And whether or not you suffer from a psychological or neurological condition, improvement in gut function and symptoms is likely to improve your quality of life and general ability to function.
There is clearly an intimate two-way connection between our guts and our brains.
There’s also ongoing research into the role that our gut microbiota play in our emotional and psychological well-being. A healthy gut and microbiome appears to support mental and emotional health as well as physical health. And a healthy diet plays a key role in supporting that microbiome.
Before embarking on a radical and unproven protocol, start by taking the obvious steps. Reduce your consumption of added sugars, alcohol, highly processed foods, and empty calories. Build your diet primarily on nutrient-dense foods like fruits, vegetables, legumes, fish, nuts, eggs, and whole grains. Eat as much plant fiber from as wide a variety of sources as you can comfortably tolerate to promote a healthy microbiome. Enjoy fermented and cultured foods as a source of beneficial bacteria.
If you still feel unwell, consider working with a qualified nutrition professional on a supervised elimination diet to identify any potential food intolerances.
But you don’t have to live for a year on bone broth and sauerkraut in order to promote a healthy gut and microbiome. And claims that this extreme and potentially harmful protocol can treat or cure psychological or neurological conditions such as autism, schizophrenia, bipolar disorder, or ADHD are supported by neither evidence nor logic.