I’m Not Going to Say, “I Told You So”

Breaking news out of the European Journal of Clinical Nutrition. Published online at pubmed.gov comes this abstract:

Metabolic and physiologic improvements from consuming a paleolithic, hunter-gatherer type diet.

Frassetto LA, Schloetter M, Mietus-Synder M, Morris RC Jr, Sebastian A.

1Department of Medicine, University of California San Francisco School of Medicine, San Francisco, CA, USA.

Background:The contemporary American diet figures centrally in the pathogenesis of numerous chronic diseases-‘diseases of civilization’. We investigated in humans whether a diet similar to that consumed by our preagricultural hunter-gatherer ancestors (that is, a paleolithic type diet) confers health benefits.Methods:We performed an outpatient, metabolically controlled study, in nine nonobese sedentary healthy volunteers, ensuring no weight loss by daily weight. We compared the findings when the participants consumed their usual diet with those when they consumed a paleolithic type diet. The participants consumed their usual diet for 3 days, three ramp-up diets of increasing potassium and fiber for 7 days, then a paleolithic type diet comprising lean meat, fruits, vegetables and nuts, and excluding nonpaleolithic type foods, such as cereal grains, dairy or legumes, for 10 days. Outcomes included arterial blood pressure (BP); 24-h urine sodium and potassium excretion; plasma glucose and insulin areas under the curve (AUC) during a 2 h oral glucose tolerance test (OGTT); insulin sensitivity; plasma lipid concentrations; and brachial artery reactivity in response to ischemia.Results:Compared with the baseline (usual) diet, we observed (a) significant reductions in BP associated with improved arterial distensibility (-3.1+/-2.9, P=0.01 and +0.19+/-0.23, P=0.05);(b) significant reduction in plasma insulin vs time AUC, during the OGTT (P=0.006); and (c) large significant reductions in total cholesterol, low-density lipoproteins (LDL) and triglycerides (-0.8+/-0.6 (P=0.007), -0.7+/-0.5 (P=0.003) and -0.3+/-0.3 (P=0.01) mmol/l respectively). In all these measured variables, either eight or all nine participants had identical directional responses when switched to paleolithic type diet, that is, near consistently improved status of circulatory, carbohydrate and lipid metabolism/physiology.Conclusions:Even short-term consumption of a paleolithic type diet improves BP and glucose tolerance, decreases insulin secretion, increases insulin sensitivity and improves lipid profiles without weight loss in healthy sedentary humans.European Journal of Clinical Nutrition advance online publication, 11 February 2009; doi:10.1038/ejcn.2009.4.

I’m going to repeat the conclusions in case they didn’t sink in:

“Even short-term consumption of a paleolithic type diet improves BP and glucose tolerance, decreases insulin secretion, increases insulin sensitivity and improves lipid profiles without weight loss in healthy sedentary humans.”

These are mighty impressive changes to occur in such a relatively short time. 10 days. This is even less than our 30-day Primal Health challenge.

These results were seen with no exercise (imagine what might have happened if they had added exercise) and with already nonobese, healthy individuals!

I hope the study speaks for itself and encourages those that have taken the 2009 Primal Health Challenge to stay the course. If you haven’t jumped on the band wagon just yet maybe this is the encouragement you need to go Primal.

Hit me up with a comment. Thanks, everyone!

Further Reading:

Conditioning Research: Stop the Presses! A Paleo Diet is Good for You

30 Day Primal Health Challenge Final Results

What’s the Difference Between Paleo and Primal?

About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

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27 thoughts on “I’m Not Going to Say, “I Told You So””

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  1. The only thing I noticed was the lean meat prescription – it would have been interesting to see the results with nice fatty meat.

  2. Actual article here for people who have access:


    Only nine subjects in the study. The numbers (especially on the lipid panel) are fairly impressive but the low number of subjects really erodes the statistical significance of the results. Also no controls (not that controls would be useful on such a small sample).

    There’s actually a far amount of sugar in the diet. Honey and juice is a listed ingredient in a number of places. Quote the dietary info: “The usual diet had a calculated K/Na intake ratio of 0.6plusminus0.3 and averaged 18% of calories from protein, 44% from carbohydrates and 38% from fats. An analyzed paleolithic diet composite had a K/Na intake ratio of 4.3 (P<0.0001) and contained 30% of calories from proteins, 32% from fat (mainly unsaturated) and 38% from carbohydrates.”

    Fasting insulin was the greatest change that I saw, from 69 +/- 63 pmol/litre to 21 +/- 7 pmol/litre. Notice that not only did it drop way off but the subjects were much more uniform in their insulin levels, which indicates the study successfully dropped all participants insulin levels.

    Fasting glucose didn’t change at all so these people weren’t insulin resistant going in.

    Since macronutrient ratios changed only a little (increased protein) in this study the conclusion would seem to be to avoid grains, legumes, and dairy products. The author’s say this was a preliminary study and they plan to follow-up with a larger study of type-2 diabetes patients.

  3. Sebastian, one of the authors, is an advocate of the acid – base theory of bone structure. This is pushed heavily by Cordain in his book Paleo Diet. Stephan of Whole Health Source is appropriately skeptical about this theory:


    As for the new dietary intervention, total saturated fat went down and polyunsaturated fat went up. Carbs basically stayed the same at 254 a day. Protein went up by 90 grams, but dietary cholesterol went down. Total calories increased.

    The meat in the sample diet is lean: pork tenderloin, chicken breast, tuna, turkey. Plenty of veggies: carrot juice, tomato juice, parsnips. Honey was in there. Carrot juice was served at almost every meal.

    I am surprised by the tuna salad made from mayo. Also, Cordain has been labeling tomatoes as a potential cause of MS, so he clearly influenced but did not plan this menu.


  4. Now anytime anyone questions me with “WHAT?!?!? You don’t eat pasta/bread/etc???” I’m going to point them to this. Thanks Mark!

  5. Mark,

    I learned this from Dr. Chris Mohr and from doing some research on how to interpret a full study.

    One study doesn’t prove the point but an abstract proves even less.

    The link above as you quote is a “study” but in essence it’s an abstract. The term makes a world of difference.

    What The Section Means:


    A summary of the main points of the article: here’s where you’ll find the purpose of the study, the hypothesis, the methods used, who was studied, and the conclusion or the findings. While you should read this first to get an general overview, a common mistake made is to draw conclusions just from the abstract.

    Now you might be right! But it sounds like you are drawing a conclusion to make your point from one abstract study.

    Not saying you are wrong per se.

    But to use an abstract to prove a point by using the conclusion line is not the correct way to interpret or read a research study.

    This is interesting news and lends itself for further research. If you can link to or find the full research paper, that would be even better.

    And again, not saying it’s wrong. Just saying using an abstract only to come to a conclusion is not correct. We’d need the whole study to draw a proper conclusion.

  6. Robert M,
    I don’t agree with your statement about statistical significance and sample size. As the number of participants decreases, the effect size needed to show statistical significance (not to be confused with biological significance) increases. So, actually, it is larger sample sizes that “erode” the importance of a test. In other words, as a study becomes larger it becomes ever easier to find P<0.05. This is why huge observational studies that include hundreds or thousands of participants always show that something is significant. We should look with suspicion upon such studies.

  7. Big believer in diet. I am 52 and have known people who eat sandwich after sandwich….OK-wholewheat breat and lite mayo….whoopee, that’s still RIDICULOUS. You need to OMIT / CUTBACK on everything after a certain age. Don’t eat so much. I only eat once a day and look back at my younger days when I had breakfast lunch, snacked all day etc. Well, alsot of 52 year olds are STILL doing the same thing as back in their 20’s / 30’s. The big key is to omit junk and cut way back….your body really doesn’t need it. Good article though. I use honey in my coffee and still feel guilty. But I have to say that your body will bloat up the older you get, if you don’t cut back. Simple fact….and your veins take a pounding besides!

  8. If the size of the study increases almost everything becomes significant. Then you have to start calculating the power of the effect and whatnot. Bigger groups are cool but are a mathematical hazzle if you ask me.

    A bigger study is of course needed and it needs not only be bigger but longer as well. But everything usually starts with the first step, not the the last and sometimes not the biggest.

  9. I have now read the whole article and I must say that I am genuinely impressed with the clear results and quick health benefits that are seen!
    If I now only could talk my diabetic father who is a white rice junkie in to this.
    And I must cut back on the salt…

  10. I am worried that your higher fat diet is not healthy although you do look very healthy. I feel that the fiber from the bran cereals is better than the additional fat from the eggs and red meat. How long did Grok live in those days-was it till only 40years old and could it match us now, with our better water, sanitation, and an aspirin a day?

  11. People are so brainwashed on diet. They FEEL this or that way because they are brainwashed. I don’t feel, I KNOW that on this diet I weight 120 for my 5′ 4″ frame and it’s a lean and muscle-packed 120,I work full-time with great energy all day, I almost never get sick (and recover quickly when I do), I am rested with 6-7 hours of sleep, and I climb, mountain bike, swim and run with people decades younger than I am and hold my own or better. Of course civilization has brought improvements that result in longer lifespan! It’s just that bran cereal is not one of them. I’ll take my meat and eggs, nuts and seeds, fruit and vegies…and race ya up a cliff!

  12. This study is one of the few studies that was ever conducted with a possible Paleo type diet. We might argue that this wasn’t The Paleo that you advocate, but it is great that researchers even bother to do intervention studies with these type of diet, especially when atkins type diets and diets high in whole grains still dominate the nutritional field.

    This whole thing started with Dr. Boyd Eaton and was improved and got more international visibility thanks to Dr. Loren Cordain’s work, who has published some of the best papers on the topic. Yet people only read his book and attack him, without even reading his scientific papers, who, by the way, are available for free at his website (who else does that???):


    Dr. Anthony Sebastian (the senior author of this intervention study) is an old man in a wheel chair with a fascinating brain and a real passion for knowledge. Moreover, he’s a highly respected researcher with more than 60 scientific papers published and he is the foremost authority on acid-base balance. The problem with this topic is that very few people in the world are familiar with it, so every critic that I’ve seen lacks a good understanding of the topic and it reveals that most of the critics have never read and/or understood Dr. Sebastian’s papers on the topic, so I suggest everyone who is skeptical of the acid-base theory to first read some of Dr. Sebastian’s papers and then make up your mind (but not before).

    Here are some of his papers:

    Frassetto LA, Morris RC Jr, Sellmeyer DE, Sebastian A. Adverse effects of sodium chloride on bone in the aging human population
    resulting from habitual consumption of typical American diets. J Nutr. 2008 Feb;138(2):419S-422S.

    Frassetto LA, Morris RC Jr, Sebastian A. Dietary sodium chloride intake independently predicts the degree of hyperchloremic metabolic acidosis in healthy humans consuming a net acid-producing diet.
    Am J Physiol Renal Physiol. 2007 Aug;293(2):F521-5.

    Sebastian A, Frassetto LA, Sellmeyer DE, Morris RC Jr. The evolution-informed optimal dietary potassium intake of human beings greatly
    exceeds current and recommended intakes. Semin Nephrol. 2006 Nov;26(6):447-53.

    Morris RC Jr, Schmidlin O, Frassetto LA, Sebastian A. Relationship and interaction between sodium and potassium. J Am Coll Nutr. 2006 Jun;25(3 Suppl):262S-270S

    Frassetto LA, Morris RC Jr, Sebastian A. A practical approach to the balance between acid production and renal acid excretion in humans. J Nephrol. 2006 Mar-Apr;19 Suppl 9:S33-40

    Sebastian A. Dietary protein content and the diet’s net acid load: opposing effects on bone
    health. Am J Clin Nutr. 2005 Nov;82(5):921-2

    Frassetto L, Morris RC Jr, Sebastian A. Long-term persistence of the urine calcium-lowering effect of potassium bicarbonate in postmenopausal women. J Clin Endocrinol Metab. 2005 Feb;90(2):831-4

    Sebastian A, Frassetto LA, Sellmeyer DE, Merriam RL, Morris RC Jr. Estimation of the net acid load of the diet of ancestral preagricultural Homo
    sapiens and their hominid ancestors. Am J Clin Nutr. 2002 Dec;76(6):1308-16.

    Sellmeyer DE, Schloetter M, Sebastian A. Potassium citrate prevents increased urine calcium excretion and bone resorption
    induced by a high sodium chloride diet.
    J Clin Endocrinol Metab. 2002 May;87(5):2008-12.

    Frassetto L, Morris RC Jr, Sellmeyer DE, Todd K, Sebastian A. Diet, evolution and aging–the pathophysiologic effects of the post-agricultural
    inversion of the potassium-to-sodium and base-to-chloride ratios in the human diet. Eur J Nutr. 2001 Oct;40(5):200-13

    Frassetto LA, Nash E, Morris RC Jr, Sebastian A. Comparative effects of potassium chloride and bicarbonate on thiazide-induced
    reduction in urinary calcium excretion. Kidney Int. 2000 Aug;58(2):748-52.

    Morris RC Jr, Schmidlin O, Tanaka M, Forman A, Frassetto L, Sebastian A. Differing effects of supplemental KCl and KHCO3: pathophysiological and clinical implications. Semin Nephrol. 1999 Sep;19(5):487-93.

  13. Stephan had something good on this study today:


    Translation: everyone improved. That’s a very meaningful point, because even if the average improves, in many studies a certain percentage of people get worse. This study adds to the evidence that no matter what your gender or genetic background, a diet roughly consistent with our evolutionary past can bring major health benefits. Here’s another way to say it: ditching certain modern foods can be immensely beneficial to health, even in people who already appear healthy. This is true regardless of whether or not one loses weight.

    There’s one last critical point I’ll make about this study. In figure 2, the investigators graphed baseline insulin resistance vs. the change in insulin resistance during the course of the study for each participant. Participants who started with the most insulin resistance saw the largest improvements, while those with little insulin resistance to begin with changed less. There was a linear relationship between baseline IR and the change in IR, with a correlation of R=0.98, p less than 0.0001. In other words, to a highly significant degree, participants who needed the most improvement, saw the most improvement. Every participant with insulin resistance at the beginning of the study ended up with basically normal insulin sensitivity after 10 days. At the end of the study, all participants had a similar degree of insulin sensitivity. This is best illustrated by the standard deviation of the fasting insulin measurement, which decreased 9-fold over the course of the experiment.

    Here’s what this suggests: different people have different degrees of susceptibility to the damaging effects of the modern Western diet. This depends on genetic background, age, activity level and many other factors. When you remove damaging foods, peoples’ metabolisms normalize, and most of the differences in health that were apparent under adverse conditions disappear. I believe our genetic differences apply more to how we react to adverse conditions than how we function optimally. The fundamental workings of our metabolisms are very similar, having been forged mostly in hunter-gatherer times. We’re all the same species after all.

    This study adds to the evidence that modern industrial food is behind our poor health, and that a return to time-honored foodways can have immense benefits for nearly anyone. A paleolithic-style diet is a very effective way to claim your genetic birthright to good health. Just remember to eat the organs and fat. And skip the canola oil and mayonnaise.

  14. Regarding comments that this publication is only an “Abstract.” That’s incorrect. Its a full study.

    The abstract is just the synopsis, a description of the study. Every scientific manuscript that is peer-reviewed has an abstract. Yes, there are only 9 subject, but each patient served as his/her own control; The changes that achieved statistical significance are believeable because of this design and the consistency of effects.

    It is very hard to obtain consistent or statistically significant results with such small test population. Its an impressive result from one study.

    David R Shalinsky, PhD

  15. OK- this is so predictable:

    just eat (drink) what comes out of your BLENDER!
    High speed, dude!

    Green veggies,and fruits are important:
    Not much else- just DRINkING the resulting smoothie!- ALL YOU NEED!

  16. I personally find the paleo diet to be a lot of common sense – sadly a lot of which we have lost over the last few years, especially when it comes to food!

  17. I am 24, 5’7″ and was 166 pounds. I have been on the Paleo diet for less than a month and have lost 11 pounds. I have never felt so good in my life. This is a life style change for me.

  18. Paleo=eating clean, basically. The cool thing about it, when I go to a party and want to cheat, I load up on sausages, meatballs, etc. Love hearing, “How can you eat that and stay in shape”? I usually don’t even bother explaining. Hate hearing, “But all that protein will raise your cholesteral”.

  19. Would someone exsplan in laymans terms the problem with eating grain! I just started the diet! But would like a explanation as ive heard so much in favor! I realize a person can have their own opinion! but not their own truth! thank you

  20. Now we need a Paleo environment without all those TVs that I turn off when not being watched everywhere I go. This activity on my part generates a consistent response – hostility. I say, “No one is watching!” They get madder. What is this about? Kind Regards, Kevin aka FitOldDog

  21. I have been on this new lifestyle for 2 years and the results were amazing. Not only that I’ve lost about 60 pounds and maintained, but my health improved significantly. When I first started the Paleo diet, I found this guide very helpful. Maybe you will do too. https://bit.ly/18OmG8t