There's Not Enough Evidence For The Paleo Diet

Eating like a caveman is said to improve your lifespan as well as helping you lose weight, but is that actually the case — and did our ancestors actually eat that way anyway? Nutritionist Rosemary Stanton examines the difficulties of the paleo diet.

Food picture from Shutterstock

Over the years, hundreds of diet books have claimed to have the perfect recipe for decreasing the national girth. They manipulate quantities of protein, fats or carbohydrates and most work in the short term because their inevitable restrictions cut energy intake.

But in the long term, few people can stick to most diets for more than a year or two. Indeed, the US National Weight Control Registry reports that only a fifth of those who intentionally lose at least 10 per cent of their weight maintain the loss for at least a year.

Many popular diets are also nutritionally unsound and so their short lifespan is a blessing. Some, such as various paleo diets, however, are recommended for life and claim benefits beyond weight loss. Such diets demand closer scrutiny.

Defining a paleolithic diet is problematic. It's supposed to be based on what our paleolithic ancestors ate.

Anthropologists have found very different dietary patterns, depending on where our ancestors lived. Most simply consumed what they could find with seasonal variations leading to substantial dietary changes.

From the mists of time?

The first of the popular paleo diets (dubbed the stone-age or caveman diet) was published in the 1970s by Walter Voegtlin, a gastroenterologist.

Although Voegtlin had published papers on various topics in his field during the 1940s and 1950s, by the 1970s he had come to believe humans should adopt a carnivorous diet because he considered our teeth and digestive tract were "more like a dog than a sheep".

Before his death in 1975, Voegtlin published a diet book that recommended meat protein and fat, but no dairy products, no salt and minimal plant-based foods (especially grains and sugar).

In the late 1980s, Boyd Eaton published a somewhat different version of the paleo diet, based largely on the diet of our East African ancestors. It featured low saturated-fat content (in keeping with the flesh of wild animals) and a one-to-one ratio of energy from plant and animal foods.

This version of the paleo eating pattern supplied moderate amounts of carbohydrates from fruits, roots and shoots.

Eaton's ideas have been amplified and publicised widely by Loren Cordain, an exercise physiologist from Colorado State University, whose website claims he is the founder of the paleo diet movement.

Cordain's paleo diet is based on grass-fed meat, poultry, eggs and seafood, fruits and non-starchy vegetables. Fats are not restricted, but grains, legumes, potatoes, dairy products and sugar are all off the table.

Cordain's group claims our ancestors were not only lean but had no cardiovascular diseases, type 2 diabetes, cancer, autoimmune diseases, osteoporosis, acne, myopia, varicose veins, gastric reflux or gout.

This is supposedly due to their lack of grains, legumes, dairy products and potatoes. Oh for some proof!

Not so fast

Some notable experts have begun to speak out about paleo diet claims. Evolutionary biologist Marlene Zuk, from the University of California, has written a book titled Paleofantasy in which she debunks many myths about the paleo diet.

You can read about it on Scientific American or New Scientist. Or you can watch this:

Anthropologist Christina Warinner from the University of Oklahoma and the University of Zurich notes that most versions of the paleo diet are closer to an early 20th century affluent farmer's diet than that of our paleolithic ancestors.

Here's her recent TEDxOU talk about it:

Another anthropologist, Katherine Milton, claims that much of what has been ascribed to hunter-gatherer populations is inaccurate. Milton notes the very different dietary patterns among groups living in different parts of the world.

She has also documented the role that both animal and plant foods have played in human evolution.

Ancient vs modern

Paleo diets recommend against the highly-processed foods rich in sugar, saturated fats and salt that characterise the modern Western diet; for this they deserve a tick.

But they ignore the benefits of many plant-based foods and some dairy products. You should check the evidence report of the Australian Dietary Guidelines for these.

Most importantly, however, the paleo diet pushes a pattern far removed from that of our ancestors. Even if domesticated animals are grass-fed, their flesh is unlike that of wild animals — kangaroo being the exception.

Free-range poultry don't just forage but are fed grains, unlike wild birds. Wild-caught fish are an option, but there are simply not enough of them to go around. Around 70 per cent of seafood consumed in Australia is also imported, often from countries where the diet of the local population desperately needs it.

Modern fruits and vegetables are also unlike those consumed in paleolithic times.

Paleo enthusiasts sometimes cite several relatively recent studies to justify their recommendations, but without exception, these are short-term and involve only small numbers of subjects. They do not constitute adequate proof of benefit or balance.

Those following the paleo diet could have low calcium and dietary fibre. Fruits, vegetables and nuts are the only sources of fibre, and calcium is found in almonds, seafood (especially prawn shells) and Asian vegetables.

Oxalic acid in vegetables such as spinach prevents absorption of its calcium and iron. Accurate nutrient levels in Australian foods are available here.

Remember too that processed meats and a weekly intake of more than 450 grams of red meat (including pork) increases the risk of colorectal cancer.

Rosemary Stanton is Nutritionist & Visiting Fellow at University of New South Wales. She does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations.

The ConversationThis article was originally published at The Conversation. Read the original article.


Comments

    So modern paleo lifestyle suggests we should steer clear of processed grain and sugary foods. That's a bad thing? Also out of curiosity, why are we the only animal on the planet that drinks milk after infancy and does that affect us in any way?

    Don't forget the exercise that comes with paleo, and the tasty food :D

      Interesting you should mention milk.
      Just saw this today:
      http://www.popsci.com.au/science/what-are-the-most-lactose-intolerant-places-in-the-world-infographic

      The first thing that struck me about that is the fact that apparently only 1/3 of the population produce the enzyme during adult-hood that lets them drink milk without a problem.
      In other-words 2/3 of the population is actually lactose-intolerant.

      Last edited 13/08/13 11:03 am

        I wonder how that goes with how many people drink coffee with milk? Come to think about it, when I don't drink milk my 2's a typically a lot cleaner. FYI. heh.

          Haha. Yeah thanks for that info. :P
          But yeah it stuck me as weird also.
          The assumption is people are so used to it they don't realise it's a problem.

            It's not a problem. The problem is fad diets and believing silly things about food and chemicals humans have used for millennia just because it's part of some new post 20th century nutrition myth.
            Does anyone remember the silly one about "no white foods"? - it said that white sugar, white bread, white eggs, milk, salt, etc were all bad and the connection was the colour. If you could get other colour alternatives like unprocessed sugar, brown shelled eggs, and wholemeal bread that was better.

            Gullibility goes on and on...

            Last edited 13/08/13 2:13 pm

      That no drinking milk stuff is extreme nonsense as well as focussing on most other aspects of the paleo fantasy as if it gives you some sort of blueprint for what we're supposed to and not supposed to eat.
      Humans are amazingly adaptable creatures and early evolution provides zero guide to what we should do now.

        You'll be surprised how little you've changed in the last 200,000 years.

          I wouldn't. The point is that we don't need to specifically evolve to handle a certain diet. We are adaptable enough to cope with a large range of environmental factors, food etc.

            A large range of food? Why is our suggested diet made up of cereal, bread, grain, pasta and cake. All of which are prominently wheat. That's the exact opposite of what you just said. Also, if we are super adaptable, why does lactose intolerance even exist?

              That's not opposite- being adaptable enough to handle a large range of foods isn't opposite to those foods. Wheat based protein became a staple because it's easy and efficient to supply large populations and keep them healthy and strong.
              Millions of other types of food are just as great for your health as substitutes but they're not all as cost effective and efficient in water and fertilizer use to grow on a large scale for mass populations. And it depends of other conditions too like in South East Asia rice was the main staple because they had a higher rainfall, in most of South America it was maze because that was the main crop they had and so on.

              Contrary to popular belief, lactose intolerance is a minority problem, so are gluten allergies, peanut allergies, and all the other types of various intolerances and allergies that exist. Humans are varied enough from all the population groups that cosseted themselves away and developed various gene prevalences and frequencies that resulted in obvious superficial things like differing skin tone, curly hair, wide noses etc that we also have a fair amount of differences that are less apparent too like various intolerances.

              Last edited 13/08/13 8:53 pm

                I can't tell if your just trolling and making this stuff up.

                "Wheat based protein became a staple because it's easy and efficient to supply large populations and keep them healthy and strong."

                - Why is 67.4% of Australia is over weight if our current diet is great at keeping people fit and healthy. Why is one-third of all human-caused greenhouse-gas emissions caused by agriculture.

                But you can believe what ever you like. My tip; Do what you can sustain and what makes you happy. For me, that's cutting back the grain and working out.

                  I'm not trolling, but you may believe I am because you might not have a grasp of the enormity of this subject, it's complexity, or the subtleties.

                  -Australians and all other first world populations supplied by industrialised agriculture are becoming overweight because of the efficiency of the farming process and our wealth that makes us able to afford so much of that food. The equation is basic: energy in, energy out. We simply consume more than we need. The type of food is not as important as the amount.

                  -Greenhouse gas emissions are caused by this sort of agriculture because it is so large scale because it has too feed a massive population. You can reduce emissions by doing certain things like cutting back on meat production and altering crop types so that they need less fertilizer etc, but unfortunately with the size of our population now (I'm talking world population here), it would be hard to make too much of a difference and it couldn't be done very fast anyway because you can't change people's eating preferences by force.

                  Cutting back on grain will do zero for your health unless you have a specific health problem like being celiac.
                  But as you say- do what you want, working out is good for you but the dietary stuff is probably mostly fantasy.

    So what is that point here? It's too hard to reproduce that diet so give up?
    I changed my diet to be more paleo-like 3 years ago. I eat less carbs and dairy, and more vegetables, with my meat intake about the same but comprising more Kangaroo, emu, crocodile, venison and seafood..
    I am fitter, get sick less and have less mood swings and hunger than before. It certainly hasn't done me any harm so far.

      I think the point is that for every wonder diet there's someone who debunks it.

      How many times have you seen the "Red wine keeps you healthy!" / "Red wine will give you cancer!" type headlines?

      At the end of the day I've just given up listening and have decided that as long as my diet's balanced, within normal ranges and works for me then I don't need to listen to the latest claims from anyone who wants to sell a book.

    wtf so basically i can have 1 steak/pork chop/lamb chop a week and eat only poultry or fish for the rest of the week, else i risk getting cancer?

    f me...

      Assuming you eat multiple meals during the day and everyday (eg. no fasting) you should be able to have 4 or 5 serves of red meat each week. A serve of meat should be between 80 and 120gms. Vegetables should make up the majority of you're meal, about 300gms and up, depending on size, muscle mass and physical activity. And possibly a small amount of whole grains (if you're eating grains/carbs), about 25-100gms.
      If you're highly active or carry a lot of muscle, these portions can be increased. Otherwise you are likely consuming too much.

    I think something broke, in place of clips I got:
    [clips provider="youtube" id="nkQhSMnRwpI" size="xlarge" align="center"]

    "Eat food. Not too much. Mostly plants."

    I've been keeping an eye on some of the paleo backlash articles. For the most part they seem to miss the point. The ideal isn't to exactly mimic a mythical ancestral diet, it's to eat food that bears some resemblance to actual food and doesn't have a 16-year shelf life.

      Thank you! If there were more people like you in the world there would be much less pseudo-science and idiotic sensationalism.

    Didn't cavemen have shorter lifespans?

      I would imagine so. Lot more things trying to eat you back then.

      Yes, but doesn't mean a lot of people didn't live to be old, they just had high infant mortality rates so that drags the average life expectancy down.

    The last part of this article was the funniest. The disclaimer. Rosemary Stanton is an published author, who has books on the market place for sale, that she will no doubtfully benefit from. Has Rosemary tried the Paleo diet? Its one thing to debunk other theories when your pushing your own, but actually living the lifestyle, and then reporting back, is another. I have met many many people who have lived the lifestyle, and its the only one they have stuck with because it works.

    People who see it as a weight loss program are the ones who are going to be disappointed the most. They measure their progress too often to see the changes they want to see. Commit to it for 3-6months, and measure the improvements in your activity, energy and overall well being. Its not easy. It challenges a lot about what you used to and what you have been told, but you start to understand what works and doesnt work for your body, and you make the adjustments as you go. Im not their entirely, but for the changes i have already, i have been blown away with how i feel.

    On another note, "Australian Dietary Guidelines " should be taken with a grain of salt. Just look back over the years, and see how it has changed. I know i would rather listen to my body, then a bunch of people who got together to set what they think my healthy living should be.

    Last edited 13/08/13 11:32 am

      "Has Rosemary tried the Paleo diet? Its one thing to debunk other theories when your pushing your own, but actually living the lifestyle, and then reporting back, is another."

      Right.. so singular personal experience trumps scientific research? Research oncologists don't need to get cancer in order to study it.

        I dont think they are same things. If your oncologists treats patients day in day in out, he is going to be better source for information in regards to managing the treatments of patients, compared to someone who might be a researcher with no first hand experience.

        I dont think there has even been remotely enough research on any of these topics for someone to put together this sort of conclusion.

        I know one thing....i let first hand experience speak for itself....both mine and others i have met. We'll let research catchup to that.....

    Looking over the comments here, I have to agree that Paleo doesn't belong in a category of 'fad diets.' Always distressing when people in health professions spend any time debunking theories they haven't much information about. Governments are in the business of agriculture. Big Business. Even if it kills your whole population, they won't mess with what agriculture is doing to our food supply. They don't require labeling that would give us the information we need to make intelligent decisions. Genetically modified food is the norm. Processed food is marketed to death with nice packaging and empty calories. Paleo is a wake up call, letting us know what real food is. We don't take the responsibility of teaching our children how to eat for good health. We let big business make their choices for them. Until we take this responsibility seriously and commit to raising a healthy society, we won't change anything.

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