I went on the Dr. Oz show in 2014 to discuss my book, Your Personal Paleo Code (published in paperback as The Paleo Cure in December 2014). (If you missed it, you can watch the clips here.)
Dr. Oz did a segment on Paleo in 2013 with Nell Stephenson and Dr. Loren Cordain, and it got great ratings. However, the feedback the show received from their viewers was that “The Paleo Diet” as presented by Nell and Dr. Cordain was too restrictive. The producers invited me on because I consider Paleo to be more of a template than a rigid prescription, and my approach doesn’t prohibit foods that aren’t typically considered to be “Paleo”—such as full-fat dairy, white potatoes, dark chocolate, and legumes.
Some people—particularly those not previously familiar with my work—were surprised to hear me tell Dr. Oz that I think eating a few servings of legumes a week is fine as long you tolerate them well. This directly contradicts Paleo dogma on legumes, which holds that we should strictly avoid them because:
- They aren’t part of our ancestral diet, and
- They contain toxic anti-nutrients like lectin and phytic acid.
But are these arguments supported by the evidence? Let’s find out.
Legumes: More #Paleo than you might think!
Are Legumes Paleo?
Back in November of 2013, Dr. Stephan Guyenet posted an article outlining the evolutionary history of legume consumption. He demonstrates that, contrary to popular belief, legumes were part of our ancestral diet.
Dr. Guyenet also points to several contemporary hunter-gatherer groups that consumed significant amounts of legumes, including the !Kung San of the Kalahari desert (who relied heavily on a legume called the tsin bean) and the Australian Aborigines (who extensively harvested the seeds and gum of Acacia trees, another legume).
This research suggests that legumes are, in fact, “Paleo.” But even if Paleolithic people didn’t eat legumes, is that reason enough to avoid them? If it is, then shouldn’t we also strictly avoid dark chocolate, coffee, green tea, and alcohol? What about the glut of breads, muffins, packaged snacks, desserts, and even candy (no, I’m not kidding) claiming to be “Paleo” that have recently become so popular? It should be obvious that our ancestors were not baking with nut flour, chowing down on truffles or drinking “Paleo” cocktails. Yet even the most die-hard, self-identified Paleo purists typically consume at least some of these foods and beverages, and don’t seem to see a contradiction in that. Why should legumes be any different?
As I’ve argued before, Paleo is best viewed as a template or a starting place,—not an inflexible, unchanging system based on (sometimes mistaken) beliefs about what our ancestors ate. Mark Sisson said something very similar in a blog post:
The anthropological record is a framework for further examination of nutritional science; it does not prescribe a diet.
A more important question to ask than whether a food is “Paleo” is how it impacts human health. Fortunately, in the case of legumes, we have a lot of modern research that can help us to answer that question.
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Should We Avoid Legumes Because of the Anti-Nutrients They Contain?
Paleo dogma on legumes holds that we should avoid them because they contain toxic anti-nutrients called lectins and phytic acid (aka phytate). Let’s take a look at each of these compounds in legumes and see if this argument holds up.
Lectins
Lectins are a type of protein that can bind to cell membranes. Studies have shown that lectins can impair growth, damage the lining of the small intestine, destroy skeletal muscle, and interfere with the function of the pancreas. Sounds serious, right?
Not so fast. There are several reasons that these results cannot be extrapolated to humans. First, the animals consumed very large amounts of lectins—much larger than a human would get from a varied diet which includes legumes. Second, the lectins were from raw legumes. Why is this significant? Because humans eat primarily cooked legumes, and cooking neutralizes the lectins found in most legumes.
In fact, cooking legumes for as little as 15 minutes or pressure-cooking them for 7.5 minutes almost completely inactivates the lectins they contain, leaving no residual lectin activity in properly cooked legumes. (2)
What’s more, other components in food (e.g. simple sugars) can bind to lectins and diminish their toxic effect. So even if there is a small amount of lectin left after cooking, it’s unlikely that it will have a detrimental effect given the presence of simple carbohydrates in legumes that can bind to the proteins. (3)
This is not an invitation to stop eating these foods! It’s simply a reminder that almost every plant we eat contains small amounts of toxins, since this is how plants defend themselves. In the majority of cases these low levels of toxins don’t harm us, and in fact, they may even provide health benefits. For example, many of the compounds we call “antioxidants”—like polyphenols found in blueberries, dark chocolate, etc.—are actually “pro-oxidants” that cause mild oxidative stress and thus upregulate our body’s natural defense systems. (5)
To my knowledge there’s only one study demonstrating humans being harmed by consuming legumes. This is the study often used by Paleo advocates to “prove” that legumes are dangerous. However, what is often neglected is that this study described a case of food poisoning that occurred in hospital patients who ate legumes that hadn’t been cooked properly. (6) Suggesting that we shouldn’t eat cooked legumes because raw legumes cause disease is like saying that we shouldn’t eat cooked chicken because we can get Salmonella from eating raw chicken.
The one lectin we may want to exercise caution with is peanut lectin, since both raw peanuts and peanut oil have relatively high lectin content. Some data in animals suggest that peanut lectin may contribute to atherosclerosis by stimulating the growth of smooth muscle and pulmonary arterial cells. (7) However, other research (including clinical trials) in both animals and humans have found that peanuts and even peanut oil reduce cardiovascular risk factors and thus may protect against heart disease. (8, 9) In light of this conflicting data, and because of other risks associated with peanut consumption such as exposure to aflatoxin, I recommend either minimizing your intake of peanuts or avoiding them entirely.
Phytic Acid (aka Phytate)
Phytic acid is the storage form of phosphorus found in many plants, especially in the bran or hull of grains and in nuts and seeds. Although herbivores like cows and sheep can digest phytic acid, humans can’t. This is bad news because phytic acid binds to minerals (especially iron and zinc) in food and prevents us from absorbing them. (It’s important to note that phytic acid does not leach minerals that are already stored in the body; it only inhibits the absorption of minerals from food in which phytic acid is present.)
Phytic acid interferes with enzymes we need to digest our food, including pepsin, which is needed for the breakdown of proteins in the stomach, and amylase, which is required for the breakdown of starch. Phytic acid also inhibits the enzyme trypsin, which is needed for protein digestion in the small intestine.
Sounds pretty bad, right? While it is true that diets high in phytic acid contribute to mineral deficiencies, it’s also true that humans can tolerate moderate amounts of it without harm (perhaps because our gut bacteria produce enzymes that break down phytate and extract the nutrients the body needs). In fact, there’s even evidence that phytic acid may have some beneficial effects. It prevents the formation of free radicals (making it an antioxidant), prevents the accumulation of heavy metals in the body, and plays a role in cellular communication.
Phytic acid in common foods (10, 11, 12)
| Food | Phytic acid (mg/100 grams)· |
| Lentils | 270–1,500 |
| Legumes (average) | 500–2,900 |
| Almonds | 350–9,420 |
| Walnuts | 200–6,700 |
| Pecans | 180–4,520 |
| Sesame seeds | 140–5,360 |
| Dark chocolate | 1,680–1,790 |
| Swiss chard | 3,530 |
| Spinach | 3,670 |
I know some of you will be tempted to stop eating spinach and Swiss chard after seeing this chart. That’s not the point! Remember, the dose makes the poison. High levels of phytic acid are harmful, but moderate amounts within the context of a diet that is nutrient-dense overall are not. Moreover, phytic acid only binds to certain minerals and prevents their absorption. There are many other nutrients in spinach, Swiss chard, and all other foods containing phytic acid that will still be absorbed when you eat them.
It’s also important to note that phytic acid can often be at least partly broken down by certain food processing methods, such as soaking and roasting. I wrote an article a while back called “Another Reason Not To Go Nuts on Nuts” suggesting that you soak and then dehydrate or roast nuts before eating them for exactly this reason. In the case of legumes, studies have shown that soaking at room temperature for 18 hours or at 140 F for 3 hours eliminates between 30–70 percent of phytic acid—depending on the legume. (13)
The takeaway is this: phytic acid in legumes is not a cause for concern as long as you’re eating them in moderation and they aren’t displacing more nutrient-dense foods from your diet. This is especially true if you are soaking legumes prior to consuming them.
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Are There Any Reasons We Might Want to Limit Legumes in Our Diet?
If you’ve read this far, you might think I’m a big advocate of legumes. That’s not the case. While they do contain beneficial nutrients and fiber (which feeds the gut flora), they are not as nutrient-dense as other Paleo foods—like organ meats, meats, fish, shellfish, eggs and vegetables—and, as I mentioned above, some of the nutrients they contain are not bioavailable due to phytic acid. (14) Because maximizing nutrient-density is one of the most important things we can do to improve our health, I think it makes sense to limit consumption of legumes to a few times a week, and to prepare them properly (i.e. soak for 18 hours and cook thoroughly) when you do eat them.
Another reason some people may need to avoid legumes is that they contain FODMAPs, which are carbohydrates that are poorly absorbed by some people and can cause gas, bloating, and other digestive symptoms.
You probably remember this song from when you were a kid:
Beans, beans, the magical fruit, the more you eat, the more you toot …
FODMAPs are probably the main reason beans have this effect on some people. But not everyone is sensitive to FODMAPs, so this isn’t a reason to avoid legumes across the board. That’s like saying that everyone should avoid shellfish because some people are allergic to them.
Final Thoughts and a Caution about Paleo Dogma
Legumes are not necessary for human health. They contain no nutrients that we can’t get from other foods—often with less trouble (i.e. no need to go through extensive preparation methods to make the nutrients more bioavailable).
That said, if you enjoy them, tolerate them well, and are willing to prepare them properly, there is no credible evidence showing that they will harm you when eaten in moderation in the context of a nutrient-dense diet—regardless of whether they are “Paleo”. The same can be said for many other “grey area” foods that are popular in the Paleo community, such as dark chocolate, alcohol, nut flour, and full-fat dairy (like butter and ghee).
I’ve been criticized on social media by some defenders of “The Paleo Diet” for my comments about legumes on the Dr. Oz segment. They insist that legumes are “not Paleo” and that they cause harm. When I ask them for proof of these claims, they almost exclusively point to Dr. Loren Cordain’s work. Dr. Cordain wrote the first mass market book on Paleo nutrition and has published many scientific papers on the subject, most of which I have read. I have great respect for his contribution.
But the idea that a single authority is uniquely capable of interpreting the research on a topic as diverse as Paleolithic nutrition, and that their opinion is infallible and unassailable, is dogma—not science. The Merriam Webster dictionary defines dogma as “a belief or set of beliefs that is accepted by the members of a group without being questioned or doubted.” Google dictionary defines it as “a principle or set of principles laid down by an authority as incontrovertibly true.”
I feel strongly that we need to guard against this, both for our own benefit and if we want Paleo to be taken seriously in the scientific community and mainstream medical establishment. We should always be ready to question even our most cherished beliefs, and prepared to change our minds in the face of new evidence. And it’s imperative that we apply the same standards of critical thinking to Paleo arguments that we do to conventional arguments.
I’m by no means perfect in this regard. I’ve had blinders on in the past about certain issues (my stance on fructose and naturally occurring omega-6 fats in foods like avocados come to mind), I’m sure I have blind spots now, and I won’t be immune to them in the future. Unfortunately, the tendency to succumb to groupthink seems to be a hardwired part of human nature. As clinicians, researchers, and scientists, all we can do is strive to be more rigorous and consistent in our thinking, and support each other in that process.
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There are more than ample studies in the scientific research literature around phytates that state ‘it is well known that phytates bind with iron and other nutrients’ etc. this is why vegetarians tend to be anaemic when they lose the benefit of haem iron. Phytates also have an impact on the environment when fed to animals. Besides all that, may I just say as a former ‘healthy’ grain and legume eater, that fifteen years of being anaemic has finally resolved due to removing grains and legumes from my diet on paleo. Finally no more iron injections and infusions. One study to start with is Potential of Phytase-Mediated Iron Release from Cereal-Based Foods: A Quantitative View in the PMC. Another is Phytate: impact on environment and human nutrition. A challenge for molecular breeding*. In addition, there would not be such an interest in messing with the genes and molecular breeding if phytates were not a problem. In countries where there is a reliance on wheat and legumes, iron deficiency is rampant. Another study showed the inclusion of wheat in a healthy non anaemic person, actually reduced their iron status. Beans are not for everyone, they’re not for me, as are other grains not for me, but if the topic is phytates then there IS enough knowledge that they do take iron, as do tannins.
Good Article Chris. The wife and I started eating mostly Paleo about two months ago. We are probably 85-90 percent paleo. We are not eating anything out of boxes or cans./ If we do have something out of a can, it is most likely a vegetable and we are doing a lot more label reading looking for hidden sugars and such. I feel better and have lost a little weight. It just feels good knowing we don’t have to work too hard to make a difference in what we are putting in our bodies and as a result feel better. Again, this was a good article, thanks for the read.
Hey Chris–have you seen this? http://news.illinois.edu/news/14/0225cholesterol_FredKummerow.html
It says high LDL is a sign of low tryptophan, and that beans may be used (for non-meat eaters) to replenish.
Excellent post, Chris. You have a very broad perspective which is interesting. I’ve been eating Paleo for over a while now by following Diane Sanfillipo’s book, “Practical Paleo.” I wanted my diet plan to be very “focused” so I didn’t deviate or research much beyond that for the first year or so. My motivation to lose weight was simply because I am healthy, and want to stay healthy, and Paleo to me makes the most sense. When I used to eat bread, pasta and processed foods, I loved the taste, but was always tired afterwards. I’ve lost a lot of weigh by following Paleo in the past 1 1/2 years. Now I’ve begun to venture beyond Diane and have started looking around to see what everyone else is saying. Glad I found you! I actually don’t like legumes and was happy when I read they were not part of Paleo. Regardless, you do have a very interesting point of view. I’d enjoy a discussion between you and some of the other Paleo “leaders.” By the way, I was in love with Stouffer’s frozen meals, particularly their Mac & Cheese. When I reached my goal, I purchased one to “celebrate” and I could not taste it. I thought there was something wrong with the package I bought so I took it back and got another and still could not taste it. It was like cardboard. After touching base with friends, I discovered that my taste buds have changed completely!! If you had told me that would happen, and that I could stop drinking diet soda, I would have told you that you were crazy. What’s really crazy is that my mouth now waters for broccoli and chicken the same way it used to water for Stouffer’s Mac & Cheese. That goes to show you that when you begin to eat “real” food, your body thanks you for it by giving you your taste buds back!
Thank you, Chris. As an MD with a strong interest in this area, I absolutely appreciate your viewpoints and approach to nutrition.
Since starting a Peleo-ish lifestyle in 2010, and listening to all views I’ve become less than comfortable with the attacks some seek to always levy against others.
Dr Cordain seemed a sensible person to me, that is until recently. The spats with Sally Fallon and now Chris point to someone who although expressing superior intellectual foundations, seems to lack the emotional intelligence necessary to deal with these issues in public.
I’ve read many of Nell’s posts and have always been struck by her dogmatic adherence to the Cordain Paleo approach. Being someone who hates dogma I’ve found the constant need for self reinforcement of this dogma to be off putting at best.
Chris, your approach works for those who are less dogmatic (some would say less intellectual), you handle yourself well under interview, and I would recommend you not get too hung up about people who hold such dogmatic views, no matter how much more intellectually gifted they may be.
Some interesting discussions in the comments.
The big one for me is the use of the term ‘Paleo’. It seems to generate a strong black & white for or against it reaction…
My tuppence worth is that due to the fact that it has a large movement behind it, that it is a collaborative approach and isn’t accredited to just one person, that many of the better dietary approaches use some form of elimination diet in the initial stages, that we don’t need another batch of ‘fad diets’ essentially saying exactly the same thing with different marketing terminology, I think for simplicity and ease of promoting global health we should all just jump onboard with the Paleo approach.
We should be using it to reconnect with our bodies and then build our own nutrition constructs from it based on how different foods make us feel, what we tolerate well, and what we like. I think having an umbrella term and template for getting people to reconnect with their nutrition, health and lifestyle is vital in order to be able to promote it effectively. So I totally understand why Chris has aligned himself with the Paleo approach rather than making up a new marketable name and I commend him for that.
Caveat: No processed foods for commercial sale should be able to be promoted using the term ‘Paleo’ including chocolate, bars, shakes, supplements etc. I think if we take the commercial element away it becomes a much more acceptable way to approach nutrition.
Personally I used a Paleo/Primal initial elimination phase and am gradually reintroducing foods to assess their impact, and it’s working fantastically. Much easier to explain this process by just saying Paleo rather than a lengthy explanation of what I am/not eating, how I’m preparing food etc…
The more you research and more you discover you don’t know, the more confusing it can become. We don’t want people giving up on their nutrition because it is confusing, conflicting, and too hard. I don’t want to see another new ‘diet book’. Remember we need to make it as easy as possible for people. Most people commenting on this post are reasonably nutrition savvy, they are not the people we are trying to reach out to! Stop thinking ‘me’ and start thinking ‘What is best for the people of the world? Given their current eating habits, knowledge, and challenges!’ If this means being a little more flexible (post elimination phase) as more quality research becomes available and allowing Paleo to absorb this information and develop organically alongside it, so it is accessible and has a positive influence on more people, I think that’s a good thing – just saying!
Excellent post, so pleased you have taken the time to look at the science. Legumes have been an essential part of man’s diet for thousands of years. Scientific research has revealed evidence that they were eaten as part of the Neanderthal diet. A healthy diet is surely one which is full to the brim of whole foods not processed ones. As a vegetarian, legumes are an essential part of my diet. A vegetarian, grain free diet has cured my son of Crohn’s Disease – one which includes legumes every day! Legumes certainly aren’t the enemy IMO unless, as you so rightly point out, people have a sensitivity to FODMAPs.
As a vegetarian I obviously don’t follow the paleo diet, however, I do believe it has enabled many people to return to eating whole foods once more and thus adopt a healthier lifestyle.
Vicky, Thank you for being one of the tolerant vegetarians who realizes that we are all different people with different nutritional needs. There actually ARE Paleo vegetarians — they even have a couple of websites.While I am not currently vegetarian (was a long time ago, didn’t work for me), I am comfortable with the concept of Paleo vegetarians — even though ancient Paleo folk were not strict vegetarians, their diets included a huge amount of plant material, and they likely went through times when they were involuntary vegetarians, at least ovo-insecto-vegetarians. And it’s great to hear of your success in eliminating Crohn’s with dietary changes — thanks for sharing!
This pretty much sums up why I feel true, strict paleo is silly. Paleo promotes many, many healthy practices that entirely contradict the typical modern diet. A paleo diet is leaps and bounds better than the average diet, there is no question about this… But to specifically limit healthful foods simply because they were not consumed during our evolution is silly.
During our evolution, we didn’t use medicine, build cities, or even live long enough to produce cancers, let alone cure them. Using this as a basis for our diets neglects many healthful foods, simply for an arbitrary reason.
Yes, our ancestors likely had a much more balanced PUFA intake, a diet higher in MUFA and saturated fats, a higher protein and carbohydrate deficient diet, while simultaneously consuming zero processed foods and large quantities of vegetable matter… Sounds like a very healthy diet because these foods, for their own intrinsic benefits, are exceptionally healthful.
Limiting dairy, say, post workout… Or even sweet potato – while fruits are acceptable (never mind the fact that the average apple has 3x the fructose they did 200 years ago, thanks to artificial selection and breeding programs) simply because apples are high in fructose and sweet potatoes are high in starch… Well, that’s just asinine.
Does this mean I can eat tofu again?
Excellent article!! I so appreciate the voice of sanity rather than that of dogma.
I’m pretty sure that sprouting beans activates phytase, which also helps reduce phytic acid? I wonder if sprouting beans, such as lentils prior to cooking is even better than simply soaking?
I’m wondering how your vision of the Paleo template differs from the long established dietary principles of the Weston A. Price Foundation?
Chris answered this question two days ago.
“From the beginning I’ve advocated an approach similar to WAPf; however, I do think most people benefit from doing a 30-day Reset (Step 1 in my book) without any grains, legumes or dairy to see if they feel better without them.”
Excellent post. Thank you for including your sources and really being critical of the evidence. I also love your bit at the end about dogma because it’s something we can very easily become blind to.
I look forward to more of your posts!
Some commenters have noted that “modern” fruits and vegetables bear little resemblance to what our Paleo ancestors must have eaten, and there is a lot of truth in that. But that is also true of modern, factory-farmed meat. Domestic animals have been bred for certain characteristics, just as veggies have. While pastured meat animals may be closer to the Paleo variety, they are not entirely the same — except for wild-caught fish and wild game, there’s little truly Paleo meat left. And some of the animals that Paleo man ate are now extinct. Even an iconic meat like bison is not exempt — they are making a comeback, but there are very few genetically pure bison to work with. They have been extensively interbred with domestic cattle. Science and nature are not helping the purists maintain their dogma. As Chris keeps emphasizing, Paleo is a template. And diet is likely only one component of the health that Paleo people enjoyed.
Great article all around Chris… Thank you for squashing dogma’s and all the hard work you do reading the science to help take the Paleo template to the next level. Cheers!
Great post Chris, very interesting, thanks!
However, I would say it’s debatable whether soaking beans at room temperature really reduces the phytic acid content. The article you refer to in you post in turn refers to a study by Iver et al. 1980 that I haven’t been able to find. But a more resent study, http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2621.2002.tb09609.x/abstract, found virtually no reduction in phytic acid content from soaking beans for 16 hours at room temperature. I believe hot water soaking is the way to go if you are to get any significant effect. But it would be great to get your comment on this, Chris!
Interesting!
Really great article. I think it’s important to continue questioning and learning about foods. Besides the good taste, and the fact it made me feel better, I like the paleo diet because it is based on science and facts about what foods do in the body–not dogma and old correlational studies and unbacked claims, which is all I have been able to find so far to support vegan and raw-vegan diets. (I’ve looked so I could learn if paleo is the right choice.)
I am wondering if soaking, then grinding and fermenting (using nut or dairy yogurt) then steaming or baking legumes further reduces the toxins. What about being resistant if they are now ground and in bread form? The same goes for fermenting nuts into cheese or yogurt, using probiotics. What does that do to the omega 3 vs. 6 ration? I also have seen no mention of beans in the mung group (ie mung, moth, and urad). They are small like lentils. Are they “safer” too? Lastly, when legumes are turned to dals (split and skin removed) are there fewer toxins? (ie are the toxins in the skin?)
If these foods have benefits and no harm, it makes sense to eat them, if only to add variety to the diet.
I wish I could tolerate beans, I love making crock pot chili with them but alas I don’t. However, perhaps my son and husband can tolerate them better? I do best on meats and fat, some veggies and fruit rarely. Sigh, it’s worth it to me to eat the way my body likes. I like the term “Paleo” because there are LOTS of cookbooks that I can use to decide what to cook for dinner, easier than just making it up by myself.
http://thepaleodiet.com/beans-and-legumes-are-they-paleo/
YEARS ago, I had read that the red “skin” that covers nuts and legumes (such as “red-skin peanuts”), was “meant” as a barrier to insects that were eating the nut/legume/seed. This made sense to me. But what I had read also suggested that, in your diet, those red skins may act to clear certain parasites from the digestive tract. I wonder if there could be any truth to that last part. ??