Saturday, November 23, 2013

Beans, Lentils, and the Paleo Diet

As we continue to explore the foods our ancestors relied on during our evolutionary history, and what foods work best for us today, we come to legumes such as beans and lentils.  These are controversial foods within the Paleolithic diet community, while the broader nutrition community tends to view legumes as healthy.

Beans and lentils have a lot going for them.  They're one of the few foods that are simultaneously rich in protein and fiber, making them highly satiating and potentially good for the critters in our colon.  They're also relatively nutritious, delivering a hefty dose of vitamins and minerals.  The minerals are partially bound by the anti-nutrient phytic acid, but simply soaking and cooking beans and lentils typically degrades 30-70 percent of it, making the minerals more available for absorption (Food Phytates. Reddy and Sathe. 2002).  Omitting the soaking step greatly reduces the degradation of phytic acid (Food Phytates. Reddy and Sathe. 2002).

The only tangible downside to beans I can think of, from a nutritional standpoint, is that some people have a hard time with the large quantity of fermentable fiber they provide, particularly people who are sensitive to FODMAPs.  Thorough soaking prior to cooking can increase the digestibility of the "musical fruit" by activating the sprouting program and leaching out tannins and indigestible saccharides.  I soak all beans and lentils for 12-24 hours.

The canonical Paleolithic diet approach excludes legumes because they were supposedly not part of our ancestral dietary pattern.  I'm going to argue here that there is good evidence of widespread legume consumption by hunter-gatherers and archaic humans, and that beans and lentils are therefore an "ancestral" food that falls within the Paleo diet rubric.  Many species of edible legumes are common around the globe, including in Africa, and the high calorie and protein content of legume seeds would have made them prime targets for exploitation by ancestral humans after the development of cooking.  Below, I've compiled a few examples of legume consumption by hunter-gatherers and extinct archaic humans.  I didn't have to look very hard to find these, and there are probably many other examples available.  If you know of any, please share them in the comments.

To be clear, I would eat beans and lentils even if they weren't part of ancestral hunter-gatherer diets, because they're inexpensive, nutritious, I like the taste, and they were safely consumed by many traditional agricultural populations probably including my own ancestors.

Extensive "bean" consumption by the !Kung San of the Kalahari desert

The !Kung San are a hunter-gatherer group that has been extensively studied by Richard B. Lee and other anthropologists.  Dr. Lee published the book The !Kung San, which contains detailed information about the !Kung San diet gleaned over his three years of fieldwork.  The !Kung San relied heavily on a legume called the tsin bean, Bauhinia esculenta.  Here are two relevant quotes from The !Kung San:
The tsin bean is the second most important food of the !Kung in the Southern parts of the Dobe area and in Nyae Nyae [second to the mongongo fruit/nut- SG].
A typical day's backload of 5 kg of tsin beans without pods has an edible/waste ratio of 70:30 and provides 3500 g of edible beans.  Back in the camp, tsin beans are processed in several ways.  Unripe beans may be sun-dried before further processing.  A batch of 50 or so beans is roasted in the shell for a few minutes in the hot ashes and sand of the cooking fire.  Slight bursts of steam from the roasting beans indicate they are ready for eating.  Occasionally a bean explodes, but without much damage.  The beans are removed from the ashes, placed on an anvil stone, and opened with a single light tap of a rock or stick.  Each bean comes apart easily into halves.  Eaten whole, the beans have a rich, strong nutty flavor.  Alternatively, the shelled beans may be pounded in the mortar and then mixed with hot water and eaten as a soup or porridge.  The tsin bean is an excellent source of protein (31.6 percent), calories, potassium, phosphorous, thiamine, riboflavin, and nicotinic acid.
By dry weight, tsin beans are 31.6% protein, 36.1% fat, 23.2% carbohydrate, and 1.0% fiber.  They are therefore between a bean and a peanut in nutritional value.

Mesquite pod consumption by Southwest Native Americans

Mesquite is a leguminous tree that was a major wild food source for Southwest Native Americans.  However, these groups ate the starchy pods rather than the seeds, so the analogy to beans and lentils may not hold up very well.

Acacia seed consumption by Australian Aborigines

Australian aborigines extensively harvested and ate the seeds and gum of Acacia trees, another legume.  Here's a quote from the paper "Acacia in Australia: Ethnobotany and Potential Food Crop" (1):
Of the sixty or so species of Acacia in central Australia, Latz (1995) states that some 50% were, or still are, eaten by Aboriginal people and it is not only the seed which is consumed. Several species exude an edible sugary gum from wounds in the stem or branches which supplies a source of energy. Others are fed upon by insects which themselves secrete an edible substance while species such as A. kempeana are the host for various edible grubs often referred to by non-Aboriginal people as witchetty grubs.
Legume consumption by Neanderthals

Neanderthals (Homo neanderthalensis) were a hominin species closely related to modern humans.  They lived as hunter-gatherers in similar environments to some humans, and are thought to have eaten a diet rich in animal foods.  However, evidence is accumulating that their diets also featured a variety of plant foods, including wild legumes and grains.  Some of the most compelling evidence comes from the analysis of Neanderthal tooth plaque, which contains recognizable evidence of plant food consumption (2):
Our data show that Neanderthals in both environments included a spectrum of plant foods in their diets, including grass seeds (Triticeae cf. Hordeum), dates (Phoenix), legumes (Faboideae), plant underground storage organs, and other yet-unidentified plants, and that several of the consumed plants had been cooked. The identified plant foods from Shanidar match well with the soil phytoliths and macrobotanical remains found at other Neanderthal sites in the Near East, whereas those from Spy show use of USOs as predicted for European Neanderthals. Neanderthals’ consumption of these starchy plant foods does not contradict data from isotope analysis, because nitrogen isotopes record only the consumption of meat and protein-rich plant foods.
Did Neanderthals enjoy wild varieties of peas and fava beans?  It certainly appears that they did.

Humans are thought to have eaten a more diverse diet than Neanderthals in the Upper Paleolithic, and one that relied more on small game and plant resources than the Neanderthal diet (at least after the "broad-spectrum revolution").  It's hard to imagine that our human ancestors in Europe passed up these plant foods that Neanderthals relied on.


Beans and lentils appear to be Paleo.  Peanuts are probably Paleo too.  But I would eat them even if they weren't.

As usual, this post is not intended to undermine the Paleo diet concept, but rather to refine a framework that I find useful for thinking about diet and human health.


Eugenia said...

I agree that most beans are ok after they're soaked for at least 24 hours. There's a research paper about it on the efficacy of soaking:

Coming from rural Greece, we always soaked our beans traditionally.

However, I'd still caution people on these four points before they go all-beans:

1. Only eat beans after 6 months to a year after you've gone Paleo. People who haven't healed yet fully are more prone to have stomach problems with legumes. But after they've healed, and fermentation/soaking has taken place, most beans are a go. SCD diet follows this approach too.

2. Prefer lentils, chickpeas, green peas, green beans, and very light colored beans. AVOID black, red, unfermented GMO soy, and fava beans. These are the ones with the highest risk in terms of upsetting your health. The "funky looking" beans are usually the ones with some poison in them (hence their weird colors to ward off predators, evolutionary-speaking).

3. I'd still not go for peanuts, especially for the US peanuts, which are prepared differently than in Europe (peanut allergy is not that common in Europe becaue of that).

4. Always clean up your lentils very carefully before you soak them. Pretty much all bags of lentils contain barley in them! They grow at the same field naturally, and so when lentils are harvested, some glutenous barley also gets end up into the bag. Also they usually contain small stones too, so you'd have to go through them anyway.

Chrome Intro said...

"AVOID black, red, unfermented GMO soy, and fava beans."

Could you provide a citation regarding this claim? Digestion issues aside, I was under the impression that black beans are one of the most nutritious beans.

Kelly said...

Eugenia, can you tell me how peanuts in Europe are differently prepared? I live in Europe and have noticed that the peanuts seem just as hard to digest for me as those in the US. Just curious...

As to Paleolithic dietary inclusion of beans and grains, I seem to remember reading recently that it is at least possible that the archeological remnants of such foods are due to the consumption of the stomach contents of prey aninmals, rather than wholesale gathering and preparation of grains and beans. In which case it would certainly seem more "natural" to eat such things in real moderation (<10%?), and that fermented forms would be preferable, as they mimic the process of ruminant digestion.

raphi said... "Having the stomach for it: a contribution to Neanderthal diets?" Laura T. Bucka, Chris B. Stringera

"Isotope analysis from Neanderthal sites such as Saint-Césaire, (Bocherens et al., 2005), Vindija (Richards et al., 2000), Les Pradelles (Bocherens et al., 2005), Engis, and Spy (Bocherens et al., 2001) indicate a high protein, high trophic level diet, similar to or even exceeding that of a wolf or hyaena. This has been interpreted as evidence that Neanderthals were top predators, skilled at hunting large mammals (Richards et al., 2000, Bocherens et al., 2001, Bocherens et al., 2005 and Richards and Trinkaus, 2009)."

They go on with the caveat..."Neanderthals in more temperate regions, or climatic phases, seem to have had different diets to those living in colder environments with a necessary focus on carnivory during severe winters"

They are careful to contextualise the presence of plant food with Neanderthals so..."Non-dietary factors that affect the build-up of calculus include chewing non-food plants, oral hygiene practices, and paramasticatory behaviour"

For example..."As discussed above, not all evidence found in the mouth should be considered to represent food. Hardy et al. (2012) also show evidence for oil shale or bitumen in the calculus, which they relate to tool hafting. People of all cultures opportunistically use their mouth as a tool, as anyone who has ever cut sellotape with their teeth can attest. Furthermore, even plant remains in calculus could result from oral (non-dietary) processing of vegetable matter, as acknowledged by Henry et al. (2011). […] oral processing may be employed to produce dye (Bond, 1996) or to soften fibres to make cord (Nash, 1991), whilst chewing vegetation for reasons of dental hygiene is also very widespread (Wu et al., 2001)"

They further expand on the potential non-necessarily diet-related presence of plants in the life of Neanderthals..."The evidence for cooked plants preserved in calculus from smoke-related compounds, methylated lipids, and heat-cracked starch grains indicates a level of sophistication in the Neanderthal diet beyond what has often been considered possible (Henry et al., 2011 and Hardy et al., 2012). Henry et al. (2011) also point out that several of the plants they identified from the calculus would require relatively complex processing before consumption. Thus this new method provides support for planning and breadth in dietary practices, which runs counter to many ideas about Neanderthal diet and cognition. Perhaps most intriguing of all the results from calculus analyses to date, however, is the suggestion by Hardy et al. (2012) that the evidence from one individual from El Sidrón points to medicinal plant use. It is this finding that we particularly question and for which we suggest the alternative hypothesis of the consumption of prey stomach contents. This hypothesis is also relevant for some of the plants that the authors suggest would have required special processing."

[post continued]

raphi said...

[post continued]

Further clarification of the point that plants can have a role other than directly diet-related..."Non-dietary factors that affect the build-up of calculus include chewing non-food plants, oral hygiene practices, and para-masticatory behaviour. Chewing increases saliva production, which may promote calculus growth, but chewed substances may also abrade the teeth and remove calculus (Lieverse, 1999). Overall, individual differences such as variation in immunological systems, or the shape and composition of teeth, may be more important than external factors such as diet (Arensburg, 1996)"

They expand on the (apparently) more grounded theory that plant foods made there way into the diet via the animals stomach contents and not directly their mouths..."We suggest instead that plants of no nutritional value to hominins (and perhaps also those that needed processing to be rendered edible) could have been ingested indirectly via the consumption of the stomach contents of herbivorous prey (chyme). This is not the first time it has been suggested that Neanderthals may have consumed the stomachs of their prey (Speth, 2010, Speth, 2012 and Hockett, 2011), but to our knowledge, the possibility of this practice confounding dietary reconstructions has not been acknowledged. Moreover, it is known that phytoliths occur in the coprolites of carnivores with herbivorous prey due to the consumption of the digestive system of the herbivore (Bamford et al., 2010), which could confuse dietary analyses if this source of plant matter was not considered."

Examples of the practice..."the Damara consume the stomach contents (and dung, which may also preserve plant fragments) of ostrich and kori bustard in the treatment of various ailments, including dehydration, malaria, and burns. These birds are perceived to have medicinal power drawn from their size and eating habits. Similarly, porcupine stomach is prized for its potency amongst KhoeSan because of the animal's diet of medicinal plants"

Reinforcing how common such a practice was..."These ethnographic accounts demonstrate how common the practice of consuming the stomach of prey has been in recent human history; this is not an unusual dietary item in terms of global food practices. Given the demonstrable benefits of consuming stomach contents, it seems likely that Neanderthals would have partaken, at least on occasion

They conclude by saying..."We are not, of course, proposing that Neanderthals would not have eaten plant foods, nor are we discounting the possibility of Neanderthal self-medication. However we suggest that, given the evidence for widespread consumption of stomach contents in recent human groups, and the likely benefits of a rich source of vitamin C and carbohydrates (to say nothing of the possible cultural or social reasons for chyme consumption) this behaviour should be taken into account as a possible source of plant foods, including ‘medicinal’ ones, in the archaeological and fossil record."

Question Dr. Guyenet:

Do you think eating partially digested legumes (for example) from animal stomachs bring about similar food preparation results, such as the inactivation of phytic acid(s)?

Jane said...

More on Neanderthals and legumes.

'This paper reconstructs the vegetal diet of the Middle Paleolithic humans in Kebara cave (Mt. Carmel, Israel) on the basis of a large collection of charred seeds and other vegetal food remains uncovered during the excavations. ... Plant remains are rarely found in Paleolithic excavations. The prevailing site formation process in most caves and open-air sites did not encourage the preservation of these kinds of organics. ... almost all plant remains (3313 seeds, 78.8% of total charred remains) belong to the legume family (Papilionaceae). ... we assume that the main source of energy in the diet of the Kebara inhabitants was the legumes...'

'Mousterian vegetal food in Kebara Cave, Mt. Carmel'

Gabriella Kadar said...

Stephan, do you know what percentage of the protein in pulses is absorbable by the human digestive tract?

Dr. B G said...

Good post Stephan.

Do you think there is any evidence that Neandethals were gliadin sensitive?

They also consumed (resistant) starch granules from roots, tubers, and nuts.

They also ate gliadin from SGG, small grain grasses.

Newbie said...

Quick question - if a legume comes canned in water, eg. chick peas, kidney beans, is that enough soaking to degrade the phytates? Do they need further cooking, or can I consider canned chick peas used to make a hummus easily digestible?
Thanks for taking the time to comment on something that is outside your area of expertise, your opinion is valued.

Scott Sterling said...

When I decided to use the Paleo framework for myself back in May 2011, I was immediately reminded of the book Makers Diet by Jordan Rubin. There is a remarkable overlap (and a few areas that don't).

It seemed to me then, and even moreso today, that Paleo will gradually accept some traditional preparation and fermentation methods. Later I learned about Weston A Price, and it seems clear that each approach informs and improves the others. I'd even include vegetarians in this, especially if they are interested in whole foods, natural and local.

Where we are different, viva la difference! Together we offer much to everyone on the Standard American Diet.

Chuck Currie said...

Yes, but, Neanderthals went extinct...could be a cautionary tale there...

I always wonder, how many people died eating raw beans before someone figured out how to properly prepare them...and who were the guinea pigs?

Nice article

cat-kit3 said...

Hi Stephan,

Do you happen to know to what degree the water-soluble vitamins are retained in the beans and lentils after soaking? I know some water is absorbed by beans (though not really by lentils), but I still have a good amount of water left over in my soaking bowl, so I don't know what this means for vitamin content of the beans.
Beans/lentils would be a great source of folate, but I'm not certain the folate is still in them, or if there's a way to reduce its loss. Thanks for any thoughts!

Matthew Green said...

Many thanks! This post seems to have done the trick!

Alysia said...

Thanks for this post. I've recently added lentils back into my diet and feel so much better eating more carbs.

Joshua Tenner said...

Quick question, does anyone have any information on lectins and auto-immune diseases? I keep hearing about it, but I never see the studies.

George Henderson said...

H-G humans and animals with high intakes of phytotoxins have strategies for dealing with the side-effects, most prominently the eating of clay or charcoal.
I wonder - quite seriously - if PRN use of clay should be part of any paleo (or vegan diet) that tries to include high levels of plant "nutrients".

Ty Fyter said...

Hi Stephan! Thanks for the post. So peanuts are a go? Does that include peanut butter?? :P


dhackam said...

Hi Stephan,

I too eat a lot of beans and I appreciate the paleo evidence. Regarding the paleo theory -- roughly that we should try to adopt the diets of our distant ancestors, and not eat what they didn't eat, but eat what they did eat (in a nutshell) -- I wonder if this theory passes scientific muster. Are the predictions that it makes, based on health, reliable?

For example, I consider it unlikely that our distant ancestors would have eaten a great deal of dairy. And some use the commonality of lactase deficiency in caucasians as evidence of this. So one would expect that people who eat a great deal of dairy today are showing gene-environment mismatching, but there is quite a large amount of epidemiological evidence, some of which I have personally peer reviewed, suggested that dairy is highly protective in terms of diabetes and cardiovascular disease. So to me, that's one blow against paleo theory.

Another example would be grains. There's evidence from the US Nurses Health Study that a diet high in grain content is protective against cardiovascular disease and diabetes - with a steep dose-response gradient. This would also seem to go against paleo theory prediction.

A third example would be nuts.

Of course, people would respond that there is paleo-archaeological evidence that there was dairy, grain and nut consumption in the paleolithic era, or looking at modern day hunter-gatherer populations, but my understanding is that the paleo diet is mostly a meat-based diet.

Unknown said...

Hi Stephen,
I know this is a little off topic, but I am wondering if/why you removed the Vitamin A toxicity post? I can no longer find it anywhere...

George Henderson said...

Eugenia makes sense
- Fava beans

Definitely a toxin and a glutathione oxidizing agent even if you tolerate them.

I would also say, use hulled lentils such as split dahl rather than "whole" legumes. The skins are where most of the toxins and FODMAPs are, and contain little of the usable nutrition.

George Henderson said...

@ dhackam,

Grains supply most carbs in the US diet, most of which are high-GI.

The Nurse's Study (whole)grain paper:

Grains may be so very unhealthy that whole grains, an unusual food in the US and a marker for "healthy living", improve health (slightly) by substituting for the consumption of even worse grain products.
In any case, there was no comparison made in the Nurses Study between people who eat grains and people who eat no grain products at all.
Many Paleo diets exclude dairy or prefer low-lactose forms, all respect that it is bad for some.
(all Paleolithic humans ate milk as children and lived in a societies where it was being consumed periodically around them so the evolutionary argument there is an especially nuanced one; also, dairy is extremely nutritious and for some it may be worth risking minor side-effects for this payoff, which would only apply to grains or legumes in a starvation scenario).

Neolithic foods could sometimes be better (dairy is conditionally the example, as may be plant foods lower in phytotoxins after selective cultivation) and Paleo humans sometimes made mistakes.

Most versions of Paleo (and for that matter LCHF) emphasize eating ample quantities of green leafy veges and other low-carb plant wholefoods as well as animal foods, and greens are the only foods that always beat all comers in the epidemiological health stakes.

Astrid said...

Thanks for that post, Stephan! After a few years on a paleo diet I've introduces legumes back into my diet a couple of months ago, and enjoy the added variety quite a bit.

Could you please elaborate on the soaking? I've been soaking my legumes for up to 48 hours in warm water with the addition of some forment, like the WAPF recommends. In my case I added a few tablespoons of waterkefir.
However, when soaking that way it seems that the skin of those legumes takes a really long time of cooking, until it gets tender. When only soaked in water, the cooking time can be reduced quite a bit.

Then again, it appears that the longer the cooking time, the more phytic acids are degraded.
I've also read a study sugesting pressure cooking of legumes (beans in particular), to reduce phytic acids even more, but haven't tried it myself yet.

milan said...

Good post Stephan
I agree almost in all with you I have beans for lunch

Jeff Rothschild said...

Gabriella -

Protein digestibility is usually around 50-85%, with germination increasing digestibility by 5-30%.

Jane said...

@George Henderson
Have you heard of David Katz? I hadn't until I came across a recent article of his. He's Director of Yale Prevention Research Center.

'Grains allegedly make us fat and stupid. ... But how about the fact that grains figure, often quite prominently, in the diets of all of the healthiest, leanest, longest-lived, most vital peoples on the planet? Look through the inventory of Blue Zones, and you find grains everywhere. The Okinawans ate them; the Seventh Day Adventists eat them; they figure in all of the best variations on the theme of the Mediterranean diet. ... And they have fared pretty well in clinical trials, too. Grains were part of the dietary pattern shown to reverse coronary atherosclerosis. They were part of the diets, more than once, shown to prevent heart attacks 70 percent of the time in high-risk people. They were part of the diets shown to lower blood pressure, and prevent diabetes in almost two-thirds of high-risk individuals. ... None of this is an argument for refined starches, obviously. ...'

Grains can even help reverse tooth decay. Chris Masterjohn tells us that Weston Price 'used rolls made from freshly ground whole wheat as part of his tooth decay reversal program, [and] showed that refined but not whole wheat produced cavities in rats.'

How do you explain all this?

Tony said...


George Henderson said...

@ Jane,
Is there any study that compares eating grains with not eating them at all?
Say, potato vs wheat?

Gabriella Kadar said...

Thanks Jeff. I suppose a person could consider 65% digestibility to be a mean estimate overall.

Europeans consider pulses to be a source of low quality protein and boost them with small amounts of animal protein.

Gabriel Haukness said...

Here is my way of explaining or reconciling the various studies of whole grain eaters, paleo, vegetarian or other dietary lifestyles. Diet is only one part of a complex puzzle. Just as important is fitness, genetics and sense of community.

Is it possible that a SAD dieter who exercises a lot and has a loving wife and low stress levels lives longer than a lonely hardcore paleo person who constantly stresses about a genetic predisposition? I could be wrong but if I had to bet my money would be on the first person.

glib said...

Chickpeas have the advantage of visually producing a spear (shoot) after about two days of soaking at room temperature. At that point not only phytates are gone (mostly), you have active enzymes such as the low numbered B vitamins being at their peak, busily turning carbohydrates into soft fiber. Traditional preparations involve stewing with tomatoes, whose acidity further counteracts the effects of phytates. Still, I find it easier to digest all manners of roots and tubers, rather than neolithic foods.

Viola said...

Legumes need to be soaked for 12-24 hours prior to cooking because that's what activates the sprouting process. Soaking after cooking does not reduce phytic acid. Canned beans are notoriously indigestible for those who suffer from intestinal problems.

J.R. Lagoni said...

Seems to be a whole lot of discussion about PROCESSING food here. Try eating your beans raw, see how much you fart, then decide LOL

Jane said...

@George Henderson
The problem with a study like that is that unless you lock people up, you can never be sure they aren't eating some refined grains. If you lock them up, it will cost you a fortune unless it's very short term, in which case their gut bacteria may not have time to adjust.

And even with a long term lock up study, you still have the problem that the immune system of some subjects may have been permanently damaged by refined grains, in such a way that they cannot tolerate any grains.

Josephus Squiggly said...


1) What would it take to falsify your hypotheses?

2) If (1) has an answer, is such research within the realm of practical possibility?

Jane said...

Hi Josephus
Do you mean, what would it take to prove whole grains are good for you? This is a problem, because to me it's already been proved, but to many people the opposite has been proved. I don't think there's any way round this, because the literature is now so enormous that nobody can read it all.

Anthony Colpo tried, and had a very long two-part article entitled 'Healthy Whole Grains?' which I can't find now. It was based on an email conversation I had with him a few years ago which he published under the heading 'The Whole Grain Scam'. I can't find that either, and I can't even find his site any more.

John Nicholas said...

I'm curious about how beans and lentils are usually prepared.

When people talk about a traditional diet and sprouted grains, it is pretty obvious that most grain products are not prepared that way and you can find a small amount of products that make a big deal about being a sprouted alternative.

Beans, on the other hand, seem to be rock hard when purchased and the basic instructions say to soak them. So when one gets beans in a can or at restaurant or wherever, are they not still being soaked somehow?

I eat in a paleo-influenced way, not religious about it but I certainly eat way less grains or beans than I did a couple of years ago. I have no noticable stomach issues eating them but I don't like to use that as my only metric. I could drop Long John Silvers fried fish on a deep dish pizza and sleep like a baby but I'm pretty sure that's not a healthy diet.

Hannah said...

Thanks for this article Stephan. I have a question about B vitamins in beans/lentils, particularly folate. Do they exist in the cooked product or no? I can't find an answer to this anywhere online. I know they are considered a great B source, but then everything I see about B vitamins says they are destroyed by cooking. I am very curious if a pregnant lady who does not want to take vitamins will be getting adequate folate from lentils and cooked liver.
Thanks a million!

D said...

Peanuts are atherogenic i.e. they fur up your arteries according to animal studies cited by Paul Jaminet on his perfect health diet blog in about September 2013.

I had been happily eating peanut butter (roasted nuts, added salt only) until then. I'd either forgotten or never known about such studies.

I've eaten other beans for 40 years with no apparent ill effects.

Honey Razwell said...

Hi Stephan,

I just wanted to make a fast comment to the public:

I want to publicly note that Stephan Guyenet is a genuine scientist in the category of people such as Carl Sagan, Phil Plait, Neil deGrasse Tyson,dr. Jeffery Friedman and his lab team etc. These indivduals are all scientists advancing human knowledge ( some deceased).

Most of Blogsphere, however, are "arm chair net surfers." They are not advancing anything- just debating about who is the top ( false) authority. There are no meaningful conversations going on- just sales and promotion...

Stephan's Blog is the only blog I read anymore.It is the one of the only truly scientific source of infomration among most of the Blogosphere who are layman.

I will not mention any names, but recently a well known blogger
(actually- a scammer) was busted misrepresenting scientific research with phony references. Being exposed and publicly disgraced, this person's blog is no longer up thanks to me. I am greateful my highly scientifically literate friend, Urgelt of YouTube, warned me years back about this blogger's scam.

We need to stop letting these self- serving fraudster salesmen blogegrs interpret science for us, people. They are shady and full of absolute certitude and never ever admit to unknowns or uncertainties. The truth is we are all groping in the dark somewhat and taking risks with our dietary decisions. Too little is yet known.

Scientists are still unravelimng how cells work and how nutrients affect them. Gut microflora appears to be extremely important for general health. We need more work on this.

The public needs to go to the PRIMARY sources - the actual research scientists themselves and their studies. Many of the well known gurus' claims are easily debunked by searching PubMed. They do not count on you doing this, though.

Thankfully, Stephan is a real scientist who fills the public in on what is going on. He admits to uncertainty and unknowns and even the rare occasion when he has been wrong- as he studies an uncertain subject . ( Even Richard Feynman got stuff incorrect sometimes). This is admireable. Both Urgelt and myself respect Stephan. And Urgelt, being highly scientifically literate does not repect too many bloggers.

Thanks, Stephan, for all of your honest work. :)

Wishing you the best !

Take care,

Nikola Pesic said...

This is an excellent blog.
Not all beans are same (evil). I personally don't mind eating very young, green peas and fava beans, even raw. Also, well soaked (12 hours) and cooked ( 1,5 hours in pressure cooker) chickpeas are something I digest very easily. White beans is like terrorist attack in my stomach, no matter how well soaked and cooked. Lentils... hmm, better not! I guess, everybody has to see for himself. If it's hard on your stomach, you probably shouldn't eat it.

Jane said...

I suppose you mean Colpo. I think you're being a bit hard on him, and I'm pretty shocked that his career has now been destroyed on account of a few articles that people could anyway have judged for themselves. I think he believed what he wrote, and he certainly put in a lot of time and effort. In my opinion he was wrong about whole grains, but who cares?

Matthew D said...

Great stuff, everyone -

Here's a short 3 min video (on legumes, phytates, and osteoporosis) that I would love to hear some analysis of by someone smarter than I am:

Stephan, thanks again for providing a space for ideation and dialogue. Great stuff.

Jane said...

Colpo's site is up again. You can get 'Healthy Whole Grains?' from 180degreehealth, but you can't get the comments. I wrote some of them myself. I think I'd want to get rid of them if I were Colpo.

Marcus Volke said...

I have to emphatically disagree with this post. Legume are loaded with antinutrients just like grains and studies clearly show that they upset digestion -

1] Greer F, Pusztai A. Toxicity of kidney bean (Phaseolus vulgaris) in rats: changes in intestinal permeability. Digestion 1985;32(1):42–6,

[2] Kordás K et al. Phytohaemagglutinin inhibits gastric acid but not pepsin secretion in conscious rats. Journal of Physiology—Paris 2001 Jan–Dec;95(1–6):309–14,

[3] Pusztai A et al. Kidney bean lectin–induced Escherichia coli overgrowth in the small intestine is blocked by GNA, a mannose-specific lectin. Journal of Applied Bacteriology 1993 Oct;75(4):360–8,

[4] Prykhod’ko O et al. Precocious gut maturation and immune cell expansion by single dose feeding the lectin phytohaemagglutinin to suckling rats. British Journal of Nutrition 2009 Mar;101(5):735–42,

[5] Pusztai A et al. Inhibition of starch digestion by alpha-amylase inhibitor reduces the efficiency of utilization of dietary proteins and lipids and retards the growth of rats. Journal of Nutrition 1995 Jun;125(6):1554–62,

[6] Ibid.

[7] Pusztai A et al. Novel dietary strategy for overcoming the antinutritional effects of soyabean whey of high agglutinin content. Br Journal of Nutrition 1997 Jun;77(6):933–45,

[8] Purhonen AK et al. Duodenal phytohaemagglutinin (red kidney bean lectin) stimulates gallbladder contraction in humans. Acta Physiologica 2008 Jul;193(3):241–7,

[9] Sitosterolemia, Guyenet S. Margarine and phytosterolemia, March 9, 2009,

[10] Freed DL. Do dietary lectins cause disease? BMJ 1999 Apr 17;318(7190):1023–4,

[11] Brown DL. Canavanine-induced longevity in mice may require diets with greater than 15.7% protein. Nutrition & Metabolism 2005 Feb 25;2(1):7, Hat tip to J. Stanton: Anti-nutritionism, L-canavanine, and the limitations of N=1 Self-experimentation,

[12] Alcocer-Varela J et al. Effects of L-canavanine on T cells may explain the induction of systemic lupus erythematosus by alfalfa. Arthritis & Rheumatism 1985 Jan;28(1):52–7, Montanaro A, Bardana EJ Jr. Dietary amino acid-induced systemic lupus erythematosus. Rheumatic Disease Clinics of North America 1991 May;17(2):323–32, Akaogi J et al. Role of non-protein amino acid L-canavanine in autoimmunity. Autoimmunity Reviews 2006 Jul;5(6):429–35, Hat tip to J. Stanton: Anti-nutritionism, L-canavanine, and the limitations of N=1 Self-experimentation,

[13] Haeney MR et al. Soya protein antibodies in man: their occurrence and possible relevance in coeliac disease. Journal of Clinical Pathology 1982 Mar;35(3):319–22,

Stephan Guyenet said...

Hi Marcus,

I don't seen any evidence in your references that fully cooked whole beans have a negative impact on the health of animals or humans. There are many human cultures that eat legumes daily and don't seem to suffer from it.

The main toxic lectin in beans that receives a lot of attention is red kidney bean phytohemagglutinin. This lectin is indeed very toxic but it's heat labile. Fully cooked red kidney beans contain very little of it and I'm not aware of any evidence that cooked red kidney beans have any harmful effects in animals or humans. Most grain and legume lectins are heat labile in fact. If you cook the beans, the lectins are denatured. I don't eat chicken raw because of salmonella and I don't eat red kidney beans raw because of lectins (not to mention the fact that they would be hard to eat). Many foods require cooking to be safe.

Some people do have problems with the fermentable fiber content of beans. This and other FODMAPs can exacerbate IBS for example. But the rest of us can eat beans, stone fruit, onions and other FODMAP-rich foods safely.

abloch said...

@ Joshua Tenner

Came across this article on the lectin and the autoimmune response:

I also just finished reading Why Do I Still Have Thyroid Symptoms? When My Lab Tests Are Normal by Datis Kharrazian and my favorite, Hashimoto's Thyroiditis: Lifestyle Interventions for Finding and Treating the Root Cause by Izabella Wentz, which explains the autoimmune response to gluten in particular, and steps to take to improve your overall health.

Ryan Wilson said...

I know some people who have problems with beans but is not me I don`t have problem with anything

Doctorfoodlove said...

Thank you for this informative article! I agree that legumes are nutritious (and delicious) and I see no compelling scientific evidence that they should be eliminated from the human diet.

Monday's Child said...

Thank you for an informative site Stephan. A few people have asked, but I have not seen an answer, are some canned beans and lentils OK to eat given they have been cooked?
I have used canned beans for years, particularly white beans and have not had a problem. I have now stopped using them and adopted a 90/10 Paleo approach to my diet and I am finding I am having digestive issues....go figure!
My question does not take into account the BPA issues with canned food just the suitability of the beans as a regular addition to my diet.

Unknown said...

Thank you for this article. You hit on the head my thoughts exactly regarding beans, legumes and peanuts. My big disklike of Paleo from the get-go has been the restriction of these super healthy foods. I realize for health reasons, some individuals may choose to not eat them and that is fine.

Stephen Coda said...

In a distant future I hope one day an anthropologist will find my fossilized kitchen and conclude the healthiest natural human diet is Poptarts and Monster Munch.

anna said...

The biggest problem I have with the Paleo diet is that it assumes that just because most people seem to have been eating a particular diet during a narrow and distant (and therefore incredibly difficult to study accurately) period of time, that's the healthiest way for everyone to eat. That seems quite illogical. During certain times in our history, humans have eaten diets that consist almost entirely of potatoes or cow blood mixed with milk. Whole populations survived in these ways. That doesn't mean it's the healthiest diet, even if it works for some populations. It also takes a bizarre approach to phytotoxins, so that lectins (which are easily destroyed with a bit of heat) are the devil, but oxalates (which cause kidney stones and, if I remember correctly, are also easily destroyed with heat) are totally fine, and same with the numerous bacteria and toxins found on all sorts of meats and "paleo-approved" vegetables. So bizarre.

Different people have different tolerances for fermentable fiber and various chemicals in plants - some that are acknowledge phytotoxins, some that are beneficial or at the very least neutral to many other people. That doesn't mean that the plant is "bad," only that it's bad for YOU. There's such a beautiful, stunning variation in the digestive abilities of our species (somewhat genetic, somewhat environmental, like all things). Let's stop making wholly unscientific, dogmatic diet choices and be a little more rational.

StanM said...

I adopted paleo/perfect health diet 4 years ago but recently developed prostate problems which many sources attribute to fat and animal protein. So I think of a change.

Davey said...

Interesting points. I never post on these things but here I feel compelled to.
"The high calorie and protein content of legume seeds would have made them prime targets for exploitation by ancestral humans after the development of cooking."
Paleo-approved foods (meat, vegetables, fruits, nuts, seeds) were consumed by our ancestors for millions of years, long before the advent of cooking (or homo-sapiens).
Furthermore, you mention various cultures who have eaten legumes with no mention of when they started eating them: Less than 10,000 years ago, I'll wager, which is far too recently.
'Ancestral' is not the same as 'Paleolithic'. Our ancestors and current hunter-gatherer societies made, and make, mistakes just like we do.