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Spilling the Beans – 10 Reasons to Avoid Eating Legumes

Jeremy Hendon | September 17

Legumes are not Paleo or HealthyHave you ever stopped to reflect on the ways that we talk about beans?

Take the most famous beans in history, for example…

Young Jack was on his way to town to sell his family’s only cow, when a stranger talked him into trading the cow for a handful of “magic” beans. When Jack got back home, his mother was so furious about having only the worthless beans, that she threw them out the window

The rest of that story took a more fantastic twist, of course.

And even today, you might off-handedly note that something isn’t worth a “hill of beans,” indicating that it’s practically worthless.

However, if you spend 2 minutes on Google right now, you can find hundreds of articles about the health virtues of beans. Many sites praise their nutritional value, their high-fiber content, their ability to help prevent cancer, and even the amount of protein you can get from legumes.

They’re such darlings in the vegetarian and vegan world that you might think beans actually lead to bags of gold, golden-egg-laying hens, and magical harps.

And yet, you’re Paleo. You avoid legumes at all costs. Are you missing out???

First of All, What is a Legume???

To over-generalize, a legumes is a bean, pea, lentil, or peanut.

To get a bit more specific, here’s a list of the most common legumes (check out this site if you want a really comprehensive list):

  • black bean
  • Boston bean
  • chickpeas
  • chili bean
  • fava bean
  • field pea
  • frijole negro
  • green beans (these are actually Paleo)
  • peas (these are actually Paleo)
  • kidney bean
  • lentils
  • lima bean
  • Mexican black bean
  • Mexican red bean
  • mung bean
  • peanut
  • pinto bean
  • red bean
  • small white bean
  • split peas
  • soy bean

Should You Eat Legumes?

Assuming that you’re not out looking for beans that will create stalks leading to giants in the clouds, this is the important question.

Most Paleo folk steer clear of legumes, but do you really know why?

While I don’t think legumes are the worst thing you can eat – things like pizza, milkshakes, and donuts are far worse – here are 10 reasons to avoid legumes:

1. Legumes are Low in Nutritional Value

Legumes have relatively few vitamins and mineralsI don’t think that every single food you eat needs to be super-nutritious. There is room in everyone’s diet for a few foods that are just food (and not perfect sources of vitamins and minerals).

Still, you should at least consider how nutritious a food is, particularly if it’s a food that you are planning on eating as a major part of your diet. And beans and other legumes like soy are definitely a major part of many people’s diets.

This might surprise you, but legumes are actually somewhat nutritious.

It’s true. Legumes tend to have more protein than most plant sources and also have a variety of minerals.

If you rank food groups on a scale of most nutritious to least nutritious (which Mat Lalonde at the 2012 Ancestral Health Symposium), then legumes fall somewhere in the middle of the scale, above grains and far above processed food like candy and sodas.

The problem is that the nutritional value of legumes is usually highly over-rated.

Proponents of legumes list nutritional values that are based almost entirely on the legume in its raw state, but once a legume is cooked, it loses much (though not all) of its nutritional value.

On the one hand, legumes are a decent source of protein, although still nowhere near as good as most animal sources, particularly when you account for the quality of protein.

On the other hand, most legumes are high in iron, magnesium, potassium, and calcium. Unfortunately, these are the primary minerals that don’t get absorbed due to high phytate levels (see #2 below).

The Takeaway is that legumes have some nutritional value, but they are not providing you anything that you can’t get more easily and better from other foods.

2. Legumes STEAL Nutrients (OK, Not Really) – Phytates

You may or may not know what phytates are, but some people (and bloggers) worry way too much about phytates.

Phytates – for the most part – are something in certain plants that prevent minerals in that plant from being absorbed by our bodies. Phytates are not “stealing” minerals out of your body.

However, so long as you’re thinking about about nutritional density (and you should be), then phytates matter, especially when it comes to many of the minerals contained in legumes (calcium, magnesium, potassium, etc.).

Phytates are the way that most plants store phosphorous, but they’re also very fond of binding to certain minerals like calcium, magnesium, and potassium. And when that happens, your body is not able to digest and absorb those minerals.

On their own, phytates are not a major concern. But if you’re planning on eating beans or lentils as a large portion of your diet, then it’s worth knowing that you’re not actually absorbing a lot of the minerals. This is particularly important if you’re considering replacing meats and animal fats with legumes, since meats and animal fats are some of the most nutritious foods you can eat.

In addition, phytates also inhibit the functioning of certain enzymes that are critical to digestion, such as pepsin and amylase. This is explained a bit more in point #4 below. For a really thorough discussion of phytates, see this Weston A. Price Foundation article.

3. Because You Hate Stomach Problems – Lectins

Beans can cause stomach problemsPaleo folks often warn everyone about the lectins in grains, but legumes are really one of the best known and well-researched sources of lectins. (Nuts and seeds are also very high.)

Lectins are a class of proteins that plants produce partially in order to protect themselves from predators. (You can read more about lectins here.) Some lectins (such as Wheat-Germ-Agglutinin – found primarily in wheat) are terrible and definitely cause problems.

The 2 main effects of lectins are that they cause “Leaky Gut” and that they lead to increased inflammation in your gut.

When you eat lectins, you may or may not feel any immediate effects, but lectins often lead long-term to all sorts of problems, such as not being able to properly absorb vitamins and minerals, food allergies, arthritis, and a variety of other issues. Here’s a post from The Paleo Mom that explains more.

Some of the most well-known lectins are Peanut Agglutinin, Phytohaemagglutinin, and Ricin, all of which are found in legumes such as peanuts, kidney beans, and castor beans.

With all of that in mind, most lectins are deactivated by heat, meaning that when you cook these foods, most of the lectins become harmless. There are exceptions to this (including both Wheat Germ Agglutinin and Peanut Agglutinin), but this is one of the main reasons that lectins are not as big of a problem as some people make them out to be.

Still, it’s something to consider. In particular, if you have any existing gut issues (IBS, for instance) or any auto-immune conditions (like Crohns or Hashimotos), then lectins are probably going to be far more problematic for you.

4. Because You Really Hate Stomach Problems – Protease Inhibitors

Proteases are enzymes that break down proteins. So Protease Inhibitors are molecules that stop proteases from doing their job.

That’s about as far into the science as I’m willing to go in this article, but if you want to know more, The Paleo Mom has a good article here.

In your body, because protease inhibitors keep proteins from being properly broken down and absorbed, your body starts producing too much of certain enzymes. When this happens, it can lead to all sorts of problems like Leaky Gut, chronic inflammation, and allergic reactions.

Soy is particularly bad about this, but most legumes are quite high in protease inhibitors.

5. And…More Stomach Problems – Saponins

Legumes are extremely high in saponins. Ok…but what the heck are saponins???

Saponins are compounds that are found in many plants, including most legumes. They have a particular chemical structure that allows them to bind to the surface of your intestinal cells.

Once saponins bind to your intestinal walls, they often cause the cells lining your intestines to either “open up” or else to die. In either case, the effect is a Leaky Gut.

Once that happens, saponins, bacteria, and other things start leaking into your bloodstream. An immediate effect is that saponins start destroying the cell membranes of your red blood cells (as well as leading to general inflammation in your body). After that, all sorts of other bad things start happening.

6. Can I Have Some Stomach Problems With That? – FODMAPS

FODMAPs are a type of carbohydrates. They’re not a problem for everyone, but for many people, they cause a variety of digestive problems.

Pretty much all legumes contain Galactins, which are a particular type of FODMAP.

If you know or suspect that you have digestive issues like Irritable Bowel Syndrome, then legumes are one of the first things that you should cut out.

Here is a great post from Chris Kresser on FODMAPs, if you want to learn more.

7. Maybe You Have a Little Bit of Weight to Lose

Legumes make it harder to lose weightCarbs are NOT “bad” for you.

However, many of us have damaged our bodies and our metabolisms through decades of eating crap and not moving around very much.

If you are such a person – particularly if you are overweight, or worse, have Diabetes – then carbs are probably not your friend.

Legumes – although they have more protein and fiber than most highly processed junk food like potato chips or cookies, still have quite a few carbs.

Listen carefully – carbohydrates are one of the last reasons that you should avoid legumes, but if you need to lose weight or control your blood sugar, then cutting legumes out of your diet can help.

8. Because You Like Your Hormones Just the Way They Are – PhytoEstrogens

Phyto means “plant,” and you generally know what estrogen is.

Phytoestrogens are not actually estrogen, but they act like estrogen. Inside your body, phytoestrogens bind to the same receptors that estrogen binds to, but phytoestrogens give a much weaker signal than estrogen. Because the signals are weak, your body will often over-produce estrogen, which will disrupt your entire hormonal system.

This can lead to a variety of problems, such as disrupted reproduction and infertility, bladder cancer, asthma, and increased incidence of Alzheimers.

9. You’re Not Feeling the Love for BPA

BPA is a chemcial found mostly in plastic. It is associated with heart disease, prostate cancer, breast cancer, miscarriage, erectile dysfunction, and abnormal reproductive development in children, although there is also recent evidence questioning whether or not BPA is really that bad.

Legumes don’t naturally have BPA, of course, but the lining of many cans contains BPA.

If you’re eating fresh legumes that haven’t been canned, then this isn’t a concern.

10. You Get Plenty of Protein and Fiber from Better Places

This is not actually a reason to avoid legumes, but it’s important to know.

Legumes tend to have more protein and more fiber than most other plants. This is particularly important for vegetarians, since protein can be hard to come by. In addition, much of the fiber in beans is soluble, which promotes – rather than disrupts – gut health.

Like I said, there are some positive qualities to legumes.

However, if you’re not vegetarian, the argument for protein is a fairly weak one, since legumes pale in comparison to most animal sources of protein, both in amount and in quality.

In terms of fiber, legumes are a good source, but contrary to popular belief, fiber is not particularly vital to one’s health, and in any case, if you’re eating enough vegetables (and maybe some occasional fruits), you’re going to get your fiber.

Peanuts are Particularly Troublesome

Peanuts are terribly unhealthyPeanuts are a particularly bad type of legume, and are something that pretty much everyone should avoid.

There are 2 particular reasons for this:

1. Peanuts contain Peanut Agglutinin, which is one of the most problematic lectins. It’s not adequately broken down by heat, so it causes all of the digestive, inflammatory, and immune problems discussed above.

2. Secondly, peanuts (unless, perhaps you’re eating them within 10 minutes of picking them from the farm) usually contain Aflatoxins, which have been definitively linked to increased risks of cancer.

Soy is the Worst Kind of Legume

Avoid all soy and tofuIf there is any legume I’d avoid above all others, it would probably be soy (with peanuts being a close 2nd). There are a variety of reasons for this:

First, when you eat soy, you typically aren’t just eating the bean itself. Most of the time, you’re eating a processed form such as tofu or soy milk, where the toxins have been concentrated and amplified.

Because of this, soy products are a huge source of lectins, phytates, and particularly phtyoestrogens, which cause all sorts of hormonal problems.

For men, this can often lead to “man-boobs” and infertility, and for women, it can also mean infertility as well as menstrual problems, as well as a host of other problems, such as bladder cancer, asthma, and increased incidence of Alzheimers. (See this article for more studies and side effects.)

The impact on infants who are fed soy formulas can be even worse and more devastating.

Moreover, soy can also lead to faster brain deterioration. It’s unclear whether this effect is caused primarily by the phytoestrogens in soy or the fact that many people who eat a lot of soy don’t eat enough good sources of B-12, such as meat.

In addition to everything else, almost all of the soy in the US is GMO.

So Should You Eat Legumes??

Despite all of the possible negative effects that I’ve pointed out, I can’t really say that you should definitively avoid legumes. Aside from peanuts and soy, they’re typically better than grains, and if I were vegetarian (especially vegan), I’d certainly eat legumes in order to get more protein.

And yet, I can’t ever imagine recommending legumes as a nutritious part of a healthy diet. There is far too little to gain from eating beans versus the potential for digestive and hormonal side effects.

However, if you are going to eat legumes, then it makes sense to eat them the same way that humans have for about 10,000 years (by soaking and sprouting them).

The process of soaking, sprouting, and/or fermenting can break down many of the lectins and phytates, and if you’re fermenting, you’ll also get some bacteria in there that is very good for your gut.

Personally, I tend to follow the lead of Jack’s mom and toss my beans out the window, hoping that something more magical will come of it. (Cheeky. But true.)

What About YOU?

Do you eat beans? Do you think they should be considered Paleo? (Honest question, because they’re not nearly as bad as grains, processed sugars, or Omega-6 oils.) Let me know in the comments below!

Images (in order): kugel, emmadiscovery, Chapendra, Tjflex2, Darwin Bell , and arimoore.

Tony Purdy - September 23

I am a DC who follows the Paleo lifestyle MOST the time. I cheat on occasion. Being from the south I grew up eating pinto beans with the ham hock thrown in for good measure. I look on it as a mild cheat and only done 2-3 times a year. Love my pintos. Great article by the way.
Tony Purdy DC

    Jeremy Hendon - September 23


    Thanks for the comment! Ham hock added to anything is delicious, IMO…

glen - September 24

Great article. I avoid legumes and this article gives me more reason to avoid them. however to answer “are legumes paleo”…. My definition of paleo is “if a caveman could have eaten it, it is paleo”. So the question is, are legumes a “natural” plant, or were they an introduced and cultivated crop (akin to grains)? If legumes have been around forever, then i’d call them paleo.

    Jeremy Hendon - September 25


    Thanks for the comment and thoughts. Personally, I prefer to base Paleo around nutrients and toxins, but I see your point. My one thought is that if our ancestors would have eaten legumes, they almost definitely would have soaked them first for a day or so.


      glen - September 25

      Hi Jeremy, I think we are in full agreeance without realising it. To me, caveman were probably “more in touch” with themselves (and didnt watch TV commercials) so im guessing they naturally and selectively ate highly nutritiious foods and foods low in toxins. To me, that is exactly what paleo is about!

Angela Roberts - October 30

All my life, I have avoided beans, because they just don’t make me feel good. Now I have a good reason to simply stay away. Even when I make the most delicious bean soup, soak overnight and change the water after making, I still get terrible stomach pains and a general overall feeling of unwellness. However, after I eat a whole porterhouse steak, I feel great. I’ve learned over time that I can just look at a food and know how I’m going to feel eating it. Beans are something I have intuitively avoided.

Jim - June 20

I cut out all legumes for a period of about 1 year, then reintroduced peanuts (lifetime lover of both peanut butter and raw and roasted peanuts). Consuming them in this manner 2-3 times per week has shown no evidence of an intolerance of any type. Still refrain from other legumes (never heard of cashews being a legume – I do consume them on occasion with no ill effects).

    Jeremy - June 20

    I completely agree – if you show no intolerance (blood inflammation markers, etc.) to legumes after excluding them for a while, there’s probably very little reason to keep them out. However, I disagree about peanuts. The mycotoxins in peanuts are a big problem and don’t always present in ways that get picked up by normal testing.

Ann Waterworth - July 31

I cannot eat legumes or any dried beans of any sort. They cause me too much trouble. So eat a little amount of organic meat or fish every few days.

Debra Nisbet - August 21

Thanks for the info. I have never been a legume eater as I don’t like them but also being on a high protein diet most of my life I have never had a need either to eat them.
The info was all very interesting..

Eva Kaufmann - August 22

very informative article, thank you! i got one question though: what about edamame? i know they fall under legumes since it’s soy, but they’re not processed and are eaten cooked. plus, if you make sure they’re not GMO (as we’re lucky enough in switzerland since importing and growing GMO is illegal), can they qualify as a good snack option once in a while? like after doing sports?

Rocío - September 1

Excellent article! Thanks. Can I have homemade peanut butter, small portions? Made from baked unsalted peanut? What if I soak them?

    Louise Hendon - September 2

    Hi Rocio – unfortunately not. As stated in the article, “Peanuts are a particularly bad type of legume, and are something that pretty much everyone should avoid.” The article explains more about why that’s so. So even homemade peanut butter is not good for you and soaking does not make it better. Sorry!

Vicky - September 2

I try to eat paleo most of the time (I have leaky gut) but I have to say I need more variety in my diet. It’s good that you qualify your “legumes are bad” article by stating that soaking, sprouting, fermenting, and cooking makes the inedible edible. So I don’t see the reason for the article. Does anyone eat legumes or grains raw? I would think these would be the only people for which this is an issue. Also, you imply that meat is all good. There are downsides to meat too. I try to always eat organic meat but the fact still remains that animal proteins are more linked to cancer than are plant proteins.

    Louise Hendon - September 2

    Hi Vicky – legumes are generally not as nutritious as many other foods (including organ meats, seafood, meats, and other vegetables) and they contain more toxins than other paleo foods. So, while they’re not the worst things to eat, there are plenty of other nutritious foods out there that don’t require soaking and cooking really well. Many people do undercook beans and grains (often to save time), and many people with digestive issues find even well cooked beans to irritate them. Also for some grains, like wheat, soaking and cooking doesn’t remove the lectins unfortunately.

J.J. - October 24

Oh boy…..Didn’t know peanuts were that “bad”….Gee’s, chopped nuts on top of my evening “treat” has been standard procedure for a long time…..I like all nuts – and add brazil nuts to my a.m. green smoothie. Also, I’m using Pea Powder (protein) in my green drink – ok, sounds like I better drop that huh? Live & learn. The more I can tighten it up – the better! Sure appreciate these bullets of wisdom and information to Shepard me through Paleo refinement.

gail - October 30

How interesting! I have long worked with the “public” and so often hear the rather adolescent cry of “say it isn’t so” or “how about just a little bit, because I like it so much…” Thank you for this comprehensive information and for continuing, (against so much wheedling) to just say “No”. Step up people,this information is invaluable, follow it. I am a 5 year-ongoing-Paleo and the more information the better; the science and consistency is there, and the PROOF is in the excellent resulting lifestyle (and perhaps in the chia (?) pudding 🙂

Marjatta - October 31


thank you for the good informative article. I used to eat a lot of (soaked, certainly non-GMO – and not soy) well cooked stewed beans – and I love them. After “going paleo” I have -to my regret – cut down and eat them once in two weeks maybe.

However, you say”but contrary to popular belief, fiber is not particularly vital to one’s health” – is this true indeed? I still have believed that fiber is very important to maintain your gut bacteria. Have I misunderstood something?

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