The Gaps in GAPS? What you need to know


BridgingTheGapAs a Certified Nutrition Consultant specializing in autism for over ten years, I have found the GAPS Diet to be one of the most effective strategies for aiding health and healing. Extensive scientific research indicates that children with autism suffer from gastrointestinal disorders more than do neurotypical children [1],[2].  We also know that there is an increase in “leaky gut,” or gut permeability in autism [3],[4], and that those with GI issues may not have enough carbohydrate-digesting enzymes (key rationale for to the GAPS diet) [5],[6]. One study by Dr. James Adams demonstrated that ASD children had greater incidence of GI disorders and an imbalance of good bacteria; and that gastrointestinal symptoms correlate with autism severity [2]. It’s because of these underlying circumstances and observations that the GAPS Diet is so highly warranted as a dietary approach.  The GAPS Diet is fundamentally helpful for gastrointestinal inflammation, dysbiosis, and digestive disorders. The GAPS diet was created by Dr. Natasha Campbell-McBride and is based on the Specific Carbohydrate Diet (SCD). SCD was popularized by Elaine Gottschall who notably helped heal her daughter of ulcerative colitis through very strict dietary intervention; she brought SCD to the autism community. The GAPS Diet calls for the avoidance of complex sugars and starches (that require carbohydrate-digesting enzymes)—and focuses on ingestion of monosaccharide carbohydrates (that do not require carbohydrate-digesting enzymes).  Eating this way reduces undigested sugars and starches in the gut, things that most pathogenic microbes (like bad bacteria) feed on.  This breaks the cycle of feeding pathogens and the inflammation and digestive disturbance they cause, and allows the body to receive nutrients from the carbohydrates it can better digest (monosaccharides).  When you remove the substances causing a problem; you can reduce digestive discomfort, improve digestive capacity, and support healing of the gut – all of which can have positive affects on autism and neurological disorders.
However, it’s frustrating to hear/read comments like, “GAPS is the only diet that will heal the gut,” or “GAPS is all you need to do—you don’t need to worry about other things (i.e. salicylate, oxalates, etc.) if you’re doing GAPS.”  This simply is not true. GAPS is an outstanding diet. Dr. Campbell McBride synthesizes tremendous research and personal experience in bringing forward a useful strategy for so many people.  However, it is not the only diet that heals.  Just today, a client that followed GAPS for two years received some lab tests that helped explain her lack of results.  Based on this new biochemical data, she wanted to switch to a new diet.  But she was hesitant because she had heard that GAPS was the best healing diet.  She asked me, “Have you ever seen a child heal on a diet other than GAPS?”  My answer, “Absolutely.”  Different diets are right for different people. There is no “one-diet-fits-all.” Because of their biochemistry or health condition, I’ve found some people require a different diet, others benefit from employing additional dietary principles with a GAPS Diet. Following GAPS can set a foundation from which to include further diet and nutrition elements required for your specific health condition. As a nutritionist that works with ALL specialized diets (not just the GAPS diet), I have a unique perspective into the varied dietary factors that influence physiological reactions and symptoms—clients (and doctors) seek me out specifically for my “knowledge base” and clinical experience in this area. I work with low salicylate/phenol diets; including the Feingold diet and Failsafe diet, the Low Oxalate Diet, yeast diets, low FODMAPS (an acronym for various fermentable carbohydrates) diet, gluten-free and casein-free (GFCF), and grain-free diets from Paleo, to GAPS and SCD.  I have years of experience helping identify food compounds that can cause reactions. Salicylates can cause red cheeks and ears, hyperactivity, irritability, aggression, sleep challenges and more.  Amines and glutamates can cause migraines, anxiety, pain, crying, hyperactivity and similar symptoms to salicylates. FODMAPS can cause digestive upset.  Oxalates can disrupt cellular function, affect energy, and cause pain, inflammation and oxidative stress—if they get out of the gut and into the cell. While improving the gut and subsequent biochemistry often improves tolerance of foods like high salicylates, it is sometimes essential to remove the salicylates to reduce the body burden and build up the sulfate pool.  If you don’t consider this, the GAPS diet alone may not be sufficient to address phenol intolerance. For most of us, avoiding extremely high oxalates is prudent.  Spinach can have 700 mg of oxalate in one serving—10 times more in one serving than some people eat in a full day.  This is enough oxalate to bind and inhibit mineral absorption (calcium and magnesium) in the whole meal. When the gut is leaky, oxalates are much more likely to get through and enter the bloodstream, especially when they are not bound to minerals.  Once in the bloodstream, they can get inside the cell and create inflammation, oxidative stress and negatively impact mitochondrial function (conditions common in autism).  Being cognizant of oxalate intake (like spinach) in the early stages of GAPS is important, and some people may need to be avoid high oxalate foods (like nuts) long term.  Oxalates and these other food compounds should be considered on any healing diet. I’ve also noticed a disturbing trend of people following a “low carbohydrate” GAPS diet.  This concerns me.  Problems can arise and one can get too low in carbohydrate, when people start cutting out more and more sugars than prudent.  The GAPS is a specific carbohydrate diet not a low carbohydrate diet. Take a fresh look at your GAPS diet… Join us to learn more about what could be affecting your GAPS success, and discover ways to take your healing to the next level. On Wednesday, March 13th, I will be leading a Nourishing Hope Support Club session on “The Gaps in GAPS.” In this webinar I will share my experience with hundreds of clients/families so you can benefit from the knowledge – without having to make the same mistakes!
This webinar is to share my experience with hundreds of clients/families so you can benefit from the knowledge – without having to make the same mistakes! We will be discussing:
  • What is the GAPS diet
  • The science behind the GAPS diet and the biochemistry underlying autism
  • The research on oxalates and phenols in autism and other disorders
  • Common pitfalls and how to avoid them
  • How to make the most of your GAPS diet
And I will answer your questions:
  • How do I determine if phenols, oxalates, or FODMAPS are a problem for me or my child?
  • Should I avoid fruit?  Does it feed yeast on GAPS?
  • Am I eating too many or too few carbs?
  • Do I need to do this diet for life?
The Nourishing Hope Support Club is the only group of its kind;  designed to support and bolster the success of those following specialized healing diets. Join the club HERE!

[1] Buie T, et al. 2010. Evaluation, diagnosis, and treatment of gastrointes- tinal disorders in individuals with ASDs: a consensus report. Pediatrics 125 (Suppl. 1):S1–S18. [2] Adams JB, Johansen LJ, Powell LD, Quig D, Rubin RA.2011. Gastro- intestinal flora and gastrointestinal status in children with autism— comparisons to typical children and correlation with autism severity. BMC Gastroenterol. 11:22.
[3] D’Eufemia P, et al. 1996. Abnormal intestinal permeability in children with autism.ActaPaediatr. 85:1076 –1079.
[4] deMagistris L, et al. 2010. Alterations of the intestinal barrier in patients with autism spectrum disorders and in their first-degree relatives. J. Pediatr. Gastroenterol. Nutr. 51:418 – 424.
[5] Horvath, Karoly, et al. “Gastrointestinal abnormalities in children with autistic disorder.” The Journal of pediatrics 135.5 (1999): 559-563.
[6] Williams, Brent L., et al. “Impaired carbohydrate digestion and transport and mucosal dysbiosis in the intestines of children with autism and gastrointestinal disturbances.” PloS one 6.9 (2011): e24585.

Julie Matthews is a Certified Nutrition Consultant who received her master’s degree in medical nutrition with distinction from Arizona State University. She is also a published nutrition researcher and has specialized in complex neurological conditions, particularly autism spectrum disorders and ADHD for over 20 years. Julie is the award winning author of Nourishing Hope for Autism, co-author of a study proving the efficacy of nutrition and dietary intervention for autism published in the peer-reviewed journal, Nutrients, and also the founder of Download her free guide, 12 Nutrition Steps to Better Health, Learning, and Behavior.


  1. Thank you for the article. Regarding the GAPS diet, I’ve been scouring the internet to find any scientific testing that supports the claims of the GAPS diet. I want to start it for my digestive issues, but I am very skeptical because I haven’t been able to find any documented double-blind studies or some form of scientific testing to back up the founder’s claims.

    While testimonials are nice to have, I have contacted some people who have tried the GAPS diet for over a year who have not seen any improvements in their condition.

    How does this diet compare to the other diets such as FODMAP? If you can point me to any scientific references, they would be greatly appreciated.

    Thank you.

  2. I have recently been diagnosed with leaky gut, pyroluria and exhausted adrenals. I was contemplating the GAPS diet before seeing the naturopath but I’m glad I didn’t. At the moment I have to avoid foods high in sulfur (although my body can tolerate eggs and watermelon). This means onion, garlic, broccoli, cauliflower and cabbage would still cause inflammation for me which I know some of these foods are allowed in the introduction phase.

    • Hey Mum of 3. It sounds like your issues may not be sulfur related. All of the problematic foods you have listed are on the ‘foods to avoid list’ for FODMAPS (fuctose malabsorption). Check out a FODMAPS list and it may give you some answers to the puzzle.

  3. Excellent article, Julie! I agree wholeheartedly that no one diet fits all; how could it? People are not cookie-cuttered! I love to teach Cooking for the GAPS diet, because what I see as a CNC is that most people that try to implement the diet have no idea how to do it well. So I teach them how to cook to do so. I will be teaching in Santa Fe this weekend, March 15 and 16. For more information, folks can check

    AND I have extended the Early Bird rate until March 13 so more people can attend.

    Thanks for all you do!!

    be well

  4. Hi Julie,

    Wish I would have known you 10 years ago when I was figuring all this out on my own. The no-phenol diet researched by an African women saved my daughter’s life. I bought Fed-Up from a bookstore in Australia. Previous my daughter had been GF/CF and SCD. When we removed the phenols especially the strawberries which were use as a reinforcer in ABA she came alive. It was a turning point for her. We are still trying to heal the gut, so this is great info. PS My oldest daughter is at Harvard and is having trouble finding like minded fellows. Any advice? She is working with Dr. Buie this summer.

    Best to you,
    Holly Masclans

  5. Thank you Thank you for this post….
    Salicylates and Oxylates are PARAMOUNT… espcially in the mitochondrial disorder/dysfunction subset of the population!

  6. Thanks for this wonderful article, Julie. I have to say, though, when I did my training with Dr. Campbell-McBride to become a certified GAPS practitioner, we were taught all about oxalates, salicylates, phenols, and the like. And if you look in the FAQ section of the GAPS website, there’s all sorts of information about these issues. So while I think things like this are important to pay attention to–and not uncommon–I think of them as not separate from but as absolutely integral to the GAPS nutritional protocol. I think sometimes people think of the GAPS protocol as being all bone broth and sauerkraut, but it’s really very comprehensive and quite alert to bodily circumstance, which is its great utility. Having said this, I do appreciate your calling our attention to these no doubt sometimes overlooked aspects of gut healing–as well as for all your great work. I know you help a lot of people. :o)

  7. I absolutely love that you are willing to tackle the complicated details of ALL these options. It can be overwhelming trying to figure out the best way to eat, and is so tempting to just follow ONE diet plan. Thank you for looking at how to individualize. I can’t wait for your webinar to learn more!

  8. I can not agree with you more Julie. Like you I have found that SCD seems to be the “only” diet for Inflammatory Bowel Disease and has quickly become the “fad” I do see that there is also a cross over with salicylate, oxalates, phenol problems with IBD as well. FODMAPS is gaining in popularity with the medical community and yet like you said there is no one-size fits all approach.
    I love your call on “The Gaps in GAPS” and will be on it to find out what the gaps really are. Thanks for this great post!!!

    • Yes, Karen! In fact, there are two studies on low FODMAPS helping Crohn’s and colitis. I love all of the nutrition science coming out today! There is new research into the biochemical differences of those with autism and digestive disorders, and study on effective new dietary approaches. This will continue to help us get answers into what diets help and why.

      Gibson, Peter R., and Susan J. Shepherd. “Evidence‐based dietary management of functional gastrointestinal symptoms: The FODMAP approach.” Journal of gastroenterology and hepatology 25.2 (2009): 252-258.

      Gearry, Richard B., et al. “Reduction of dietary poorly absorbed short-chain carbohydrates (FODMAPs) improves abdominal symptoms in patients with inflammatory bowel disease—a pilot study.” Journal of Crohn’s and Colitis 3.1 (2009): 8-14.

  9. Excellent article Julie. I totally agree that there is no one-size-fits-all approach to any health condition. We are all bio-individual and the answer is to find or modify dietary approaches to fit the needs of the individual. As you point out just because there is a large client population that benefits from GAPS doesn’t mean that it is the only approach.

    Thanks also for sharing so many of the different dietary strategies you work with. I think it’s helpful for people to know that there are many different ways to approach healing with food.


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