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A meta-analysis of the Paleolithic nutrition pattern; an interview of authors

A modern paleolithic nutrition patternJust today, the American Journal of Clinical Nutrition – the most prestigious nutrition journal in the world – published a systematic review and meta-analysis of the paleolithic nutrition pattern (the Paleo diet).

The audio interview below is with study authors, Hanno Pijl, M.D., Ph.D., and Esther van Zuuren, M.D., both of Leiden Unversity in the Netherlands. They, along with authors Eric Manheimer and Zbys Fedorowicz, first performed a systematic review of six online publication libraries for all possible qualifying research. From there, they winnowed the list to four studies, pooling together 159 subjects for their analysis, looking for mean differences in primary endpoints related to metabolic syndrome: 1) waist circumference, 2) blood pressure, 3) triglycerides, 4) HDL cholesterol, and 5) blood sugar concentration. Secondary endpoints included change in body weight, even though some of the studies included in the analysis tried to prevent weight change so that the results would be less confounded by it. Weight loss, while healthy for someone who are overweight, can also improve these endpoints independently, making it harder to know if it is the nutritional properties of the diet or the weight loss that influenced results. We discuss this specifically in the interview, which you can listen to here in its entirety:

On SoundcloudiTunes, Google PlayStitcher, and YouTube

 

Why Try This Dietary Pattern?

The quick rationale for this nutritional pattern is as follows: Hunter gather societies – either anthropological estimates of ancestors and assessments of modern-day native groups – seem significantly less burdened, if not almost completely free from,  degenerative diseases that plague modernized societies. Additionally, when members of natural living societies adopt modern diets and lifestyles, their health worsens. When some now-modernized people return to their former natural living lifestyles, they show marked improvements in their overall health. See research by Kerin O’Dea for examples. These observations segued into several uncontrolled trials, first evaluating the paleolithic nutrition pattern over short timeframes, and the results were positive at improving metabolic health markers in healthy people.

 

Is Paleo Really Paleo?

Before I continue with this article, I must comment that a modern-day Paleolithic-based nutrition pattern is veritably nothing like an actual Paleolithic diet. Virtually all the plants we eat today are products of agriculture (and we’re eating vastly less plant diversity than our ancestors, too), and for the most part, for most people, the meats (mostly muscle, and few organs) we eat today are from domesticated animals. Together, the nutritional impact of meat and vegetables today is distinct from the set of nutrients delivered by meats and plants of our ancestors, not even to mention the extensive list of cooking techniques we use to process foods.

In other words, the foods entering out body today are very different that what entered the body 10,000 years ago, or earlier. And this is totally fine. A modern-day Paleo diet is meant to help us eat the foods that are more similar to our ancestral past, and by doing so, help us avoid the nutritional pitfalls that literally dominate our modern food environment. The Paleo diet isn’t meant to be a perfect replica of a diet in that time period, it’s a concept that is meant to guide us to better food choices given the food options we have access to now.

 

The Paleo Diet Is in Its Awkward Teenage Years

The appeal of the concept of Paleo is strong for many. The state of modern health and wellness is nothing less than scary: long-term health outcomes based on nutrition are extraordinarily hard to study, some recommendations on what we eat can appear downright wacky, and authoritative guidance can shift. In 2014, Paleo was the most searched health term globally, yet organizations like the US News and World Report listed Paleo as dead last in their recommendations of sound diets, citing lack of substantive evidence. For many people who have experienced real health benefits making the change to Paleo, or simply people who have bought into the argument, this condemnation leads only to further distrust of nutritional authorities. Yet, while I would be embarrassed to be a part of a group of nutritional figures that rated the Paleo diet last amongst their recommendations, they are not incorrect to claim that more evidence is needed. It is, and that’s why I’m pleased to share this audio interview of the authors of the rigorous meta-analysis with you.

 

Results, Interpretations, and Discussion from the Analysis

Paleolithic nutrition resulted in greater short-term pooled improvements on each of the 5 components of the metabolic syndrome than did currently recommended guideline-based control diets, however, this change did not reach significance for two of the five components (HDL and fasting blood sugar).

Paleo outperformed guideline-based control diets on each 5 components of metabolic syndrome Click To Tweet

This is very impressive. To rephrase, this says that the Paleolithic nutrition pattern outperformed (some) diets currently recommended to treat this condition. Some very important questions, however, came up during the interview, including a discussion on what characteristics of the diet pattern might be generating the positive results. Essentially, any component of the diet that limits inflammation is likely crucial.

Interestingly, Paleo is most popularly thought of as the exclusion of grains, legumes, and dairy. It is important to acknowledge, however, this is disputed by researchers, such as Karen Hardy of the Universitat Autònoma de Barcelona, who argue that starch, as in the form of tubers, was also a staple food for our ancestors starting 800,000 years back, once humans began to use fire for cooking. Hanno and I discuss the nuance of carbohydrate consumption in today’s world, talking about how it can be safe for many, and how it’s the form consumed that is the key distinction. Hanno went as far as to say that processed carbohydrates are not healthy for anyone, even those free of any metabolic disease. I interpret this statement to mean that the more you include processed carbohydrate in your diet, the more your risk for metabolic disease will rise (if that pattern is maintained over the course of decades). In our chat, I referred to this article I wrote entitled Why dietary fat is fattening and when it’s not, where I referenced the top 10 sources of calories in the US diet.  Most of the calories are from processed carbs, but I opine that health status of US citizens would be very different if those calories were from whole-food carbohydrate sources instead.

We also discussed the discrepancy between these findings, with the epidemiological findings that whole grains (for T2DM, and for CVD), especially oats (hat tip Jamie Scott), and fermented dairy are healthy for our metabolisms and blood lipids. Indeed, another point discussed is how the Paleolithic nutrition pattern, while continuing to develop a sterling reputation in clinical trials, may indeed be unnecessarily restrictive. Time will tell, hopefully, but it’s research just like this that will draw more resources and interests to drill down on these important questions and nuances, to help us make increasingly informed nutritional decisions.

 

Conclusion

A Paleo diet is often thought of as…

  1. INCLUDED: Vegetables (including root vegetables), fruit (including fruit oils, e.g., olive oil, coconut oil, and palm oil), nuts, seafood, meat, and eggs.
  2. EXCLUDED: Dairy, grain-based foods, legumes, extra sugar, and nutritional products of industry (including refined fats and refined carbohydrates).

But a better representation of Paleo is more like this…

  1. INCLUDE: Vegetables (including root vegetables), fruit (including fruit oils, e.g., olive oil, coconut oil, and palm oil), nuts, fish, meat, eggs, and tubers.
  2. EXCLUDE: Dairy, grain-based foods, legumes, extra sugar, and nutritional products of industry (including refined fats and refined carbohydrates).

And actual health likely stems from this (We’ll call it “Natural Neolithic” of “NatNeo“), but more research is needed.

  1. INCLUDE: Vegetables (including root vegetables), fruit (including fruit oils, e.g., olive oil, coconut oil, and palm oil), nuts, fish, meat, eggs, tubers, dairy (especially fermented), legumes, and whole grains.
  2. EXCLUDE: Added sugars and nutritional products of industry (including refined fats, and refined carbohydrates).



  • Ruri Zbys Fedorowicz

    Brilliant well covered and debated.. would probably be a good bet for a 3 person TED talk

    • danpardi

      A TED Talk: I like that idea, @rurizbysfedorowicz:disqus!

      • Ruri Zbys Fedorowicz

        I have lots more ‘ideas’ btw this systematic review was one of them😊

        • danpardi

          Okay, what’s next, Zybs?

          • Ruri Zbys Fedorowicz

            LETS FIX THE TED TALK !!

          • Ruri Zbys Fedorowicz

            ok Dan the man with the Plan so no more ideas lets set a PLAN to do a TED Talk we have been looking at the options and possibilities BUT youre the MAN so lets have the PLAN 😉

          • danpardi

            Hi @rurizbysfedorowicz:disqus, I don’t know anyone at the TED organization, but most TED talks are now satellite organizations that use the TED brand. We can keep our eyes out for talk possibilities and then someone can submit a proposal when the opportunity arises.

  • Esther van Zuuren

    Dan, you did great job in very limited time. Thank you for the opportuitto share our work with you

    • danpardi

      Thank you @esthervanzuuren:disqus, and likewise! I really enjoyed speaking with you both.

  • PantherFan83

    I understand there are concerns about them containing anti-nutrients, but I still don’t understand why legumes and nightshades aren’t paleo. If/when a paleolithic man came upon beans, peppers, or tomatoes they would have surely eaten all they could gather.

    • danpardi

      HI PantherFan83, here is the rationale from Loren Cordain, Ph.D. for:

      Nightshades: http://thepaleodiet.com/wp-content/uploads/2015/08/Paleo-Paper-nightshades.pdf

      Legumes: http://thepaleodiet.com/beans-and-legumes-are-they-paleo/

      • maurile

        “The evidence for wild legume consumption by humans is as strong as it is for any plant food consumed during the Paleolithic. If legumes aren’t Paleo, then what is Paleo?” — Stephan Guyenet (http://wholehealthsource.blogspot.com/2014/03/book-review-your-personal-paleo-code.html)

        • danpardi

          @maurile, I eat both nightshade a and legumes. My diet is closest to the ‘Natural Neolithic’ described above.

          • maurile

            I understand that you were simply sharing Cordain’s rationale and not necessarily endorsing it. I just think we need to distinguish between The Paleo Diet(TM) — i.e., Cordain’s version — from the actual diet consumed by our ancestors during the paleolithic period. The first excludes legumes, but the second, by and large, did not.

          • Ruri Zbys Fedorowicz

            We should stop using the word ‘diet’ in this context as there is no one/single paleo diet the appropriate terminology? paleolithic nutrition pattern… our systematic review emphasises that clearly

          • danpardi

            I really like Paleolithic nutrition pattern. It’s a better way to describe it.

          • Ruri Zbys Fedorowicz

            actually I think we might also move away from the word Paleolithic and would prefer PijlEO ie Pijl (as in Hanno P) Eating Options

        • Ruri Zbys Fedorowicz

          The fact is we DO NOT have reliable evidence of what they did or did not eat but we DO NOW have reliable evidence that a nutritional pattern largely devoid of processed food (ie what our paleo ancestors did NOT have access to), does have a beneficial effect on the components of the metabolic syndrome most notably those relevant to type 2 diabetes.

  • Bebido

    The last diet option (and healthiest) sounds an awful lot like the so-called Mediterranean diet…

    • danpardi

      Yes @Bebido, and the Mediterranean diet has always performed well in clinical health studies. It’s the diet that most closely describes my own. Yet, it’s good to note that a comparison diet in one of the studies included in this meta-analysis was a Mediterranean diet with education on the efficacy of the Lyon Heart Study, and that the Paleo outperformed it.

      • Ruri Zbys Fedorowicz

        Evidence of EFFECT & Evidence of BENEFIT… over 2 National Dietary Guidelines which certainly included Med style ‘diet’

    • Something that nearly all studies that involve the Mediterranean diet miss out on is the importance of fasting in the Greek-Orthodox religion. The seven countries study was the first to highlight the health benefits of the people living on Crete, and many of those people lived in rural areas and were deeply religious. That means they had ~180-200 days/year of some type of either partial or total food restriction. It’s certainly a healthy dietary pattern, but like Thelonious Monk and Miles Davis, it’s about the space between the notes that counts a lot.

      • danpardi

        @jeffrothschild:disqus, great points! I wonder if this means that the Paleolithic nutrition pattern plus fasting would be even more beneficial that what’s seen in these studies.

  • Mike Keyes

    Wasn’t it because the med diet was grown in Sulfur rich soil

  • carbsane

    How can you say that paleo outperformed recommended diet when in the largest of FOUR totally disparate studies — 44% of total subjects — the control group came nowhere near following recommendations?

    • danpardi

      Hello @carbsane:disqus, sorry for the delay. I was off the grid camping. Thanks for this comment and graph. To me, there is always at least two key aspects of any diet study: 1) the diet(s) intended to be studied or compared, and 2) the diet(s) actually practiced by the participants. Both provide valuable information. Obviously, if making judgments about the efficacy of a dietary style, compliance rates should be discussed. After all, the compliance of participants in a study doesn’t necessarily represent the best possible compliance scenario. Diets more difficult to perform might still be achieveable with the appropriate amount of support, and therefore might be a realistic intervention. At the same time, it’s useful to see how well groups adhere when given equal degrees of guidance and support. It would be unfair, in my opinion, to have the control group receive education and coaching, while the intervention group receives delivered meals. That would certainly be stacking the desks in favor of the non-control intervention.

      Having said that, I do think it’s fair to conclude that the paleolithic nutrition pattern out performed these control diets in this pooled data analysis, because that is what this analysis shows, and the intervention conditions were comparable within each of the four studies included. As I concluded in my own article, I think this warrants more extensive investigation to see if these benefits hold in a larger population, and critically, if these benefits can be maintained over time. Importantly, in the Mellberg study – which to other readers of this comment string is one of the four studies included in the meta analysis, and the one referenced here by @carbsane – showed significant improvesments in things like fat mass, waist circumphrence, body weight at 6 months, but the differences in these parameters were no longer significant at 24 months.

  • Paleo Huntress

    Why specify tubers separately from root vegetables? Tubers ARE root vegetables.

    These descriptions are identical except that you recommended tubers twice.

    INCLUDE: Vegetables (including root vegetables), fruit (including fruit oils, e.g., olive oil, coconut oil, and palm oil), nuts, seafood, meat, and eggs.

    INCLUDE: Vegetables (including root vegetables), fruit (including fruit oils, e.g., olive oil, coconut oil, and palm oil), nuts, fish, meat, eggs, and tubers.

    What you describe at the end is the Weston A Price Foundation diet. And many people who couldn’t get lean on it came to Paleo where the removal of grains and legumes made all the difference in the world.

    • danpardi

      While tubers are classified as a root vegetable in agriculture, the timing of regular consumption of them for humans – and so whether they are considered a part or even cornerstone of the paleolithic nutrition pattern – has been a subject of much debate. Some think we consumed lots of them up to 800k years ago (Hardy), contributing significantly to the enlargement of our brain – while other’s think their significant consumption of did not occur until much close to the Neolithic era (Ben-Dor).

      When writing this I considered two options. You see the one I went with, but the other way to express this is as follows:

      INCLUDE: Vegetables (including root vegetables, but not tubers), fruit (including fruit oils, e.g., olive oil, coconut oil, and palm oil), nuts, seafood, meat, and eggs.

      I opted to include tubers appended to the second version because I thought it highlighted the difference a little more clearly for most readers. In other words, here is the same list, plus tubers.

      You wrote: “What you describe at the end is the Weston A Price Foundation diet. And many people who couldn’t get lean on it came to Paleo where the removal of grains and legumes made all the difference in the world.”

      I don’t doubt that this is true for a lot of people. Cutting out grains removes a big chunk of processed foods in the diets of many people (e.g., breads, cakes, pastry, pizza), and these food make up a very large fraction of calories in the human diet.

      I wonder how people would do if they restricted their grain consumption to einkorn, farro, spelt whole grains. My guess is that some will still do better on a lower carb paleo diet but others would do just fine.

      Thanks for the response.

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