A correspondent asked me to look into the GAPS diet.  I did. I was sorry: it was a painful experience. What a mishmash of half-truths, pseudoscience, imagination, and untested claims!

GAPS stands for Gut and Psychology Syndrome. It is the invention of Dr. Natasha Campbell-McBride. According to her, a wide variety of health problems can be traced to a single cause: an imbalance of gut microbes.  She cites ancient wisdom: Hippocrates said all diseases begin in the gut. She says science confirmed that wisdom when it discovered that 90% of all cells and all genetic material in the human body belongs to the gut flora. She says the modern world poses many dangers for the gut flora, and once it is damaged, the health of the whole body enters a downward slide towards disease. She claims that autism and ADD, OCD, schizophrenia, epilepsy, depression, and numerous other ailments are all digestive disorders.

According to her, the gut flora is “highly organized” (?) and is dominated by beneficial species. When the balance is out of whack, children don’t digest and absorb food properly, and they develop all kinds of symptoms in the digestive tract and elsewhere. The microbes convert the undigested food into hundreds of toxic substances, which clog the body with toxicity. The brain becomes so clogged with toxins that it can’t process sensory information, so children are unable to learn and develop skills. When the toxicity levels are low, they may show single signs like hyperactivity or dyslexia. With higher levels, autism develops. 80% of these clogged children have a mixture of symptoms that don’t fit into any diagnostic category, but it is important for them to be identified as suffering from GAPS early in life to prevent permanent damage.

Explaining the Autism Epidemic
She explains why we are seeing more autism. It’s not so much an autism epidemic as an epidemic of abnormal gut flora. She says autistic children were born perfectly normal (not true), but after birth they developed abnormal gut flora which created toxicity.  Babies get their gut microbes from Mom as they pass through the birth canal, microbes that originated in the bowels of both parents.  They get pathogenic microbes because the parents’ good microbes were wiped out when they took antibiotics earlier in life. The disruption of gut flora leads not only to autism but to many other diseases.

Another factor is that breastfeeding went out of fashion. Bottle fed babies develop abnormal gut flora. Breastfed babies don’t because the mother has developed an immune response to her own abnormal gut pathogens and immune factors are transmitted in breast milk. Another factor: oral contraceptives have “a devastating effect on gut flora”. (Really? Where’s the evidence?) Processed foods allow pathogens to proliferate in the gut. High fructose corn syrup contributes to the problem.

And vaccines are also to blame. She subscribes to the “Too many too soon” philosophy. She says babies with abnormal gut flora are not fit to be vaccinated like healthy people. Their immune systems can’t respond well to the vaccine. And vaccines themselves are harmful. She says they were developed to make profits for Big Pharma rather than to benefit children. She says genetically modified organisms that may not be safe are used in vaccines because natural ones can’t be patented.  Antibiotics directly damage immune cells. Vaccines may cause type 1 diabetes, celiac disease, etc.  Siblings of children with ADD, etc. should not be vaccinated until their gut flora has been normalized. (This kind of misinformation and vaccine rejection threatens herd immunity and public health.)

Is There a Test for GAPS?
She says there are ways to diagnose it, follow its progress, and determine when normal gut flora has been restored. First you get a health history from the parents, then you get a urine test for microbial metabolites, and a stool analysis for gut flora. (As far as I could tell, these are questionable tests offered by questionable labs like Genova, and interpretations of the results are not based on any credible scientific evidence.)

The Diet
It is a healing diet that is intended to last only for a couple of years. It excludes sugars and starches, prohibiting potatoes, rice, pasta, bread, wheat, flour, dairy products, and sugar in any form other than fruit. It allows certain vegetables and fruits, meats, fats, nuts, and broths. You can purchase an Apple app that lists all the foods allowed and not allowed. Die-off phases are to be expected, where the dead “bad” bacteria release toxins and the symptoms get worse.

It starts with a GAPS Introduction Diet and proceeds in seven stages.

The body is starved, so you must start with easily digested foods. The first stage allows only room temperature water, probiotics and a very limited diet. When other foods are gradually introduced, if the patient gets black diarrhea, pain or any other digestive symptoms, wait a week and try again. (Dangerous advice, because black diarrhea could mean gastrointestinal bleeding and a medical emergency.)

As foods are introduced, you can do this (bogus) sensitivity test: put a drop of food on the wrist at bedtime. If there is an angry red reaction in the morning, avoid that food for a few weeks, then try introducing it again starting with a small amount.

In stage two, raw organic egg yolks are added, (a great way to get Salmonella) along with homemade yogurt and kefir, fermented fish, homemade ghee, and certain kinds of stews and casseroles.

Stage 3 adds avocado and special pancakes made with only butter, egg, and squash. Other foods are gradually added. And so it goes, up to Stage 7 which is the full GAPS diet. Eventually patients are allowed some kinds of starches, but sugar and refined starches are permanently banned. Ground-up nuts replace flour for baking, and fruits replace other sweeteners. The whole family should go on the protocol and change their lifestyle.

After the period of the diet, she says many of her patients choose to continue with the diet permanently since it is very healthy and allegedly prevents all kinds of diseases and obesity.

She strongly advocates detoxification. She realizes the liver detoxifies for us, but she thinks it gets clogged up and needs help. She knows this because mercury, lead, arsenic, and formaldehyde can be found on analysis (sure they can, with bogus tests like the “urine toxic metals test”  and and the Heavy Metal Screen Test). Juicing provides effective, gentle detox. Baths with Epsom salts, seaweed powder, bicarb, and cider vinegar provide gentle but “incredibly effective” detox. Fermented foods supply probiotic bacteria that take out harmful chemicals and hold them until detox can remove them. But you must be careful. Too much fermented food can cause a die-off that releases toxins, so you temporarily get worse.  (Isn’t it curious how many alternative treatments make things worse before they get better? It’s a convenient “out” when the patient fails to improve.) You should make fermented foods at home and make homemade yogurt from raw milk (never mind the risk of infection).

She says fasting is another way to detoxify: when you stop eating, your body re-directs its energy to other jobs such as removing toxins and parasites and healing. She says it has an excellent record of curing all sorts of incurable conditions from rheumatoid arthritis to cancer. (I don’t think so!)

Who Is This Woman?
Natasha Campbell-McBride earned an MD in Russia, where she practiced as a neurologist and neurosurgeon. After moving to the UK she got a degree in Human Nutrition and now practices as a nutritional consultant in a clinic in Cambridge, England. Her website provides a long list of diseases and conditions she may be able to help with:  GAP syndrome, tummy pain, aggressive behavior, cystitis, epilepsy, PMS, ADD, autism, heart problems, migraine, psychosis, poor memory, and 74 other health problems. I noticed that arthritis is not on the list; I wonder why?

She had never encountered an autistic child until her own child was diagnosed with autism at age 3. This threw her into a fast learning curve as she researched ways to help her child that the medical establishment didn’t offer. She came up with her own hypothesis, invented a new disease (GAPS) and an effective treatment all by herself, and her son recovered completely.

She Sells Things
Her online store offers probiotics, books, DVDs, essential fatty acids, fermented cod liver oil, high vitamin butter, coconut oil, immune support supplements, essential oils, Cinderella’s organic multipurpose cleaner, hand sanitizers, a garden hose filter so your children can engage in “clean water fun”, and Urban Moonshine Organic Bitters, because bitter flavors are essential to good health because they stimulate the digestive system. You can be trained to become a GAPS practitioner in a two-day course for $1175. Training includes a business starter package.

Scientific Evidence
As the Wikipedia article succinctly and politely puts it, “Science is not known as yet to support…GAPS theories, or claims of psychological benefits.”  It seems science hasn’t yet bothered to test it: I couldn’t find any published studies on GAPS or the GAPS diet. Campbell-McBride is not a researcher and has not published anything. She might at least have written up a formal case report on her own son and his apparent cure so we could try to understand what actually happened. Instead, all she has given us is testimonials from grateful patients.

Other Questionable Claims
She says a lot of other things that are odd, questionable, or even demonstrably wrong. Some examples:

  • If you listen to your desires for food, you will be able to digest that food and it will only do you good because you ate it at the right time, when your body asked for it.
  • Avoid perfumes and scented products because they destroy your sense of smell.
  • Processed foods alter your sense of taste.
  • Brush your teeth with olive oil instead of toothpaste: this Ayurvedic procedure detoxifies the mouth. (No fluoride?)
  • Avoid processed salt and use natural unprocessed salt such as Himalayan or Celtic salt that contains more than 90 minerals. (How much of each? Surely not enough to matter.)
  • The autonomic nervous system shifts back and forth from sympathetic to parasympathetic dominance, which require different foods. One likes meat and fat, the other needs more plant foods. Your body will tell you which you need more of.
  • There are daily and seasonal cleansing cycles and building cycles, each requiring different nutrients: animal foods build, plant foods cleanse.
  • Our needs depend on our heredity. If your ancestors were Vikings or Eskimos, you will need to eat lots of fish.
  • Avoid vegetable and cooking oils. Polyunsaturated fats are bad because they are chemically mutilated. 50% of the fat in our diet should be saturated.
  • Don’t test your blood cholesterol. Testing is pointless and potentially harmful. Old people with high cholesterol are healthier and live longer.
  • Eating cholesterol-rich foods is essential to produce enough vitamin D.
  • Vitamin D deficiency causes cancer, diabetes, heart disease, mental illness, autoimmune illness, obesity, bone and muscle disease, high blood pressure, chronic pain, poor immunity and susceptibility to infections.
  • Instead of cholesterol, test CRP and insulin levels.
  • Our soils are worn out. We would have to eat 2 kilos of apples today to provide the nutrition one apple used to give us.
  • Using volcanic rock dust in organic gardening improves nutrition, and if used on a global scale, it would enable the soil to absorb enough excess atmospheric carbon to stabilize global climate change.
  • The alarming growth of degenerative disease in our modern populations to a large degree is due to relentlessly decreasing levels of minerals in our food.
  • Black elderberry is one of the most powerful anti-viral remedies known to man.
  • Meat, fish, nuts, oily seeds are easier to digest than other foods.

Red Flags
There are plenty of red flags here: the “lone genius,” the “one cause” of most disease, the die-off and “wait a while and try again” explanations to keep patients on the diet when it is making them worse, the unvalidated sensitivity and diagnostic tests, the detoxification language, the bold but unsubstantiated claim of total reversal of autism, the dangerous recommendations for raw eggs, raw milk, and saturated fat and against vaccines and cholesterol testing, and more. Birds of a feather: she is associated with the Weston Price Foundation and was featured on Mercola’s website (both notorious sources of misinformation).

The GAPS diet reflects serious gaps in Dr. Campbell-McBride’s reasoning and in her understanding of science. There is no published evidence to support it. The early introductory stages may not provide adequate nutrition; the full diet is probably healthy but is onerous. It seems very unlikely that it could accomplish all that is claimed. Without testing, there is no way to know whether it benefits or harms patients.



  • Harriet Hall, MD also known as The SkepDoc, is a retired family physician who writes about pseudoscience and questionable medical practices. She received her BA and MD from the University of Washington, did her internship in the Air Force (the second female ever to do so),  and was the first female graduate of the Air Force family practice residency at Eglin Air Force Base. During a long career as an Air Force physician, she held various positions from flight surgeon to DBMS (Director of Base Medical Services) and did everything from delivering babies to taking the controls of a B-52. She retired with the rank of Colonel.  In 2008 she published her memoirs, Women Aren't Supposed to Fly.

Posted by Harriet Hall

Harriet Hall, MD also known as The SkepDoc, is a retired family physician who writes about pseudoscience and questionable medical practices. She received her BA and MD from the University of Washington, did her internship in the Air Force (the second female ever to do so),  and was the first female graduate of the Air Force family practice residency at Eglin Air Force Base. During a long career as an Air Force physician, she held various positions from flight surgeon to DBMS (Director of Base Medical Services) and did everything from delivering babies to taking the controls of a B-52. She retired with the rank of Colonel.  In 2008 she published her memoirs, Women Aren't Supposed to Fly.