Don’t lie.  When you first heard of the “caveman diet”, you scoffed didn’t you?  Or perhaps you grunted a little.  Sure sounded like another fad diet.  I personally would’ve picked the name “Encino Diet” to make it more competitive with Atkins, but hey caveman marketing is a bit primitive.

Fortunately for us, this doesn’t appear to be a scam.  Many patients with autoimmune or autoimmune-like conditions seem to benefit by changing to a diet based on evolutionary principles.  No doubt you’ve hemard of some of the most popular ones: Specific Carbohydrate Diet (SCD), Paleo, Primal, GAPS, and more.  There are a ton of resources out there on each diet, so I’ll focus on the main differences between these 4 most popular diets & delve into success metrics, where available, rather than the details of each diet.

Yo McFly I’m borrowing the DeLorean to take a closer look at these dietary blasts from the past:

1) Paleo Diet, aka the Stone Age Diet

By far the most popular one, led by Loren Cordain & Robb Wolf.  The focus is on all-natural (i.e. grass fed) animal fats and natural fats (ghee, avocado etc), and of course, no carbs. (Update: starchy root vegetables, white rice, and other starches without antinutrients are allowed according to some Paleo expert)  The basic tenet is that we’re simply not evolved to optimize digestion and absorption of agricultural products.

Success: There are no controlled studies on this diet yet, but lots of >90% success rates reported by various doctors internationally.  Dr. Jean Seignalet in France conducted a trial on autoimmune patients, with success being defined as 50% reduction in symptoms, and here are the results:

Rheumatoid arthritis: 200 (sample size), 80% (success rate)
Lupus: 13, 100%
Multiple Sclerosis: 33, 97%
Fibromyalgia: 41, 97%
IBS: 220, 98%
Crohns: 40, 100%
Chronic Fatigue Syndrome: 11, 85%


(Note: I left out some illnesses that aren’t the focus of our blog.)

2) Primal Diet

Mark Sisson is the main proponent.  Basically the same as Paleo except it allows full-fat dairy.  According to Mark’s pictures, shirts should also be avoided:

Chronically Ill Patients First Look at Primal Diet

Wouldn’t mind having that body though!

Chris Kresser is another big proponent of Paleo that has incorporated dairy such as grass-fed butter and kefir into his protocol with much success.  He talks about not tolerating more than a teaspoon of kefir at first, but slowly building up to pints a day.  I’ve heard similar stories from ME/CFS patients that benefit from fermented dairy.  His theory is that taking probiotics via kefir actually changes your microbiota or gut flora to allow your gut to tolerate dairy.

*Success: *I couldn’t track down any statistics specific to the Primal Diet, but due to its similarity to Paleo I would imagine if you could tolerate dairy, the statistics for Paleo might be a good reference.

3) Specific Carbohydrate Diet

This was developed by Sydney Valentine Haas, MD.  At first glance it sounds like a low-carb diet, but the basic tenet is actually that carbs feed overgrowth of yeast & bacteria in the gut, so limit both the amount & types of carbs to well-absorbed.  The major difference from Paleo: legumes such as beans are allowed, and like Primal, dairy is allowed.


“Proponents of the diet claim there is an 80% recovery rate for Crohn’s disease and a 95% recovery rate for diverticulitis.” –

“According to ARI, 71% of parents say SCD is beneficial for their child.”

And most impressive, results of a pilot study done on Irritable Bowel Syndrome:

“Notably, 9 out of 11 patients were able to be managed without anti-TNF therapy, and 100% of the patients had their symptoms reduced. ”

4) GAPS Diet:

Based on the SCD diet, and developed by Dr. Natasha Campbell-McBride.  The main difference from the other diets is the focus on  *healing *the gut, as opposed to just feeding it foods that are optimally digested & absorbed.  Main difference from SCD:

emphasis on bone broth and fermented foods, less beans, gradual implementation of dairy casein to tolerance starting from Ghee (which has virtually no lactose).

Update: I previously wrote GAPS was recommending vegetarian diets now, but I couldn’t verify this.

Success: *Because this diet’s the newest of the list, statistics are lacking so far.  In my personal opinion, based on what we know about leaky gut though, the use of bone broths to provide easily-absorbed nutrition and *seal the gut en route to building tolerance of fermented products makes this diet especially appealing for severe LGS.

Final Thoughts:

There is far more similarity within these diets than there is different.  GAPS was mostly developed as an improvement to SCD, and Primal was mostly developed as an improvement to Paleo.  In the end, many practitioners agree that ultimately an elimination diet where you eliminate a food for 30 days and then add one thing in at a time (and monitor how you feel) is the way to figure out which foods and amounts of those food your body reacts to.

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