The Diet Comparison SCD | Primal | Paleo | GAPS

There is a lot of information out there on the 4 diets for Autoimmune diseases. How do YOU pick the right one? Do research! In the “About Me” post, I explained my love of Paleo and why I chose SCD.

I will recommend starting with a gluten test. Not to see if you are gluten intolerant, because you still should avoid it, but to KNOW. I was like, no way I am intolerant, I love pasta and cookies! Ya well my naturopath ordered the test and yes I am gluten sensitive. I think hearing that, made following the diet so much easier. I didn’t want to kill myself anymore.

I love this article-read through and leave your comments.

From my understanding ONLY–If I am wrong please correct me. SCD and GAPS have same base and Paleo/Primal have the same base. The main differences are: Paleo- some carbs/starches are allowed that are not allowed on SCD. Paleo allows no legumes and SCD does. SCD/GAPS/Primal allow fermented/cultured dairy- Paleo none.

Paleo, Primal, SCD, GAPS: Which Diet Is Best for Autoimmune Illness?

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 named it Encino Diet with Brendan Fraisier as posterboy 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 heard of some of the most popular ones: Paleo, Primal, Specific Carbohydrate Diet (SCD), GAPS. 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.

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

1. Paleo 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 low carbs (starchy root vegetables, white rice, and other starches without antinutrients.) 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%

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. 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 (SCD) 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: properly-prepared legumes such as beans are allowed, and like Primal, dairy is allowed.


Autism Research Institute’s survey found that with 71% of parents noted improvement in their kids from SCD.

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

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. Gut And Psychology Syndrome (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).

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.


In recap, Paleo/Primal is a Whole Body Idea (General well being and/or weight loss). SCD/GAPS are Gut Specific for Healing (still great for general well being).

Original article credits

13 thoughts on “The Diet Comparison SCD | Primal | Paleo | GAPS

  1. michelle

    Your cinnamon toast recipe sounds YUMMY!! I’m doing the Whole 30. What can I use in place of honey?

    thank you

  2. Cheryl

    Thanks for tying these diets together at a glance!

    Have been reading a bit about histamine-intolerance–that this may be a “missing piece” of dietary-health connections among sensitive individuals, the added piece being a reduction in histamine ingestion/production-release in the body, and increasing the body’s capability to degrade histamines (a healthy gut producing adequate DAO (diamine oxidase) enzyme is critical here).
    One key way of addressing histamine reduction involves ingesting only the VERY FRESHEST (ie, as close as possible to “the cow still mooing”/fish gasping, etc..) meats; otherwise, bacteria begin converting the naturally-occurring histidines into histamines. Apparently tuna tends to have the largest concentrations of histidine. Additional interventions further address & optimize reduction of histamine and its impact in sensitive individuals.
    Sounds like something worth trying after reaching a plateauing of benefits with other dietary modifications in place.

  3. cia parker

    The SCDiet only allows a few kinds of dairy: it advocates home-made yogurt, especially from goat milk, that is fermented for at least 24 hours to predigest the casein and lactose. It allows some hard cheeses, which are lower in casein than soft cheeses, and it allows a certain kind of cottage cheese, but nothing else. My daughter is autistic, and, like most autistic kids, also has bowel disease, in her case severe chronic constipation. The GFCF diet worked miracles, but after a few months stopped working, possibly because of the ALA I started giving her to chelate the mercury from her brain. It may increase yeast and microbial overgrowth in the intestines. I started her on the SCDiet in April, getting recipes from Taking her off all grains worked, relieving her symptoms within days. I’m mostly cooking from Paleo cookbooks now, it’s so close to the same thing. I give her So Delicious coconut yogurt in the evening, an hour after her digestive enzyme at supper, for its probiotics. I don’t know if it will eventually heal her gut and she can go back to eating normally, but for now she’s happy and doing well (me not so much, since I’m an ethical vegetarian and don’t eat what I make for her).

  4. Linda Allebach

    I have battled IBS and about 6 other autoimmune disease issues for going on 40 years now. Suffice it to say I’ve been around the block about medical doctors not having a clue…and also was not able to deal well with any kind of medications that just address the symptoms anyway… I stumbled onto the SCD about 4 years ago and have been on it ever since. Probably because I’m a little older it does feel like a lot of work at times, but the change from where I was to where I am is absolutely incredible and definitely makes the time spent worthwhile. IBS still isn’t defined by most doctors, including Social Security ones, as a debilitating disease but it sure can and does appreciably alter one’s life. I had to early retire because of it and my last two jobs were greatly affected. I report at least twice a month to my GP and have instructed her on all the details so she can share them with her gastroenterologist colleagues. Your website is really well done and I’m glad I found it! Thanks so much for all your hard work and please keep it up for those of us who are always looking for new legal recipes. Muchas gracias y via con Dios!

  5. Mica

    Make sure the yogurt doesn\’t have carrageenan, a know carcinogen and causes of other gut issues. Please google not and also cornucopia institute has a list of what products have it and not.


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