Why Wednesday: Why No Legumes?

Hello and welcome to Why Wednesdays where I will help you understand the why’s behind Paleo recommendations so that you can transform your life and the lives of people around you. By digging deep into the why’s I have transformed a diet into an enjoyable lifestyle that frees up time and space in my life for what really matters – spending time with the people that matter most and being fully present in each moment with them – instead of a constant unhealthy obsession with food and weight. My friends, family and clients that eat Paleo have more energy, are more productive, and are more content with th eir bodies, among other amazing results.

In the old world, diet gurus, nutritionists and doctors told you what diet to follow, what to eat and nothing else. This worked for awhile, but results were usually temporary because they lacked an essential factor that I am about to share with you. The public was expected to take information at face value in this old world and accept it with no question as fact and truth. No one explained any complexities or processes to the public because they didn’t think they could handle it. Instead, they watered everything down until the truth was lost in the process. The old world was about control… control of information and knowledge vital to your success.

In the new world, people want answers. Old world methods of simple prescriptions no longer work. All real and lasting results contain this essential element absent in the old world and that is the why. The why is so important because it gives you a reason and a choice. By knowing the why’s, you are empowered with the knowledge to make decisions about food on your own… without needing the government, me, or anyone else to tell you what to do. The why is essential to transforming diet after diet after diet into a liveable enjoyable lifestyle. I think you can handle the truth. I am confident that you can understand the physiology necessary to make competent decisions about your food. In this new world, I understand that you are no longer content with recommendations without credible reasons. I know you want a deeper level of information than you were given credit for in the past and I want to honor that. Thus, Why Wednesdays is born!

Legumes are a source of contention among many because, on one hand, they contain so many vitamins, minerals and fiber, but on the other, they are not recommended as a staple on Paleo. Today, I will tell you exactly why legumes are not the greatest and how you can eat them occasionally instead.

Legumes usually form in pods. The most common legumes are soy, peanuts, lentils, peas, and beans. Legumes are notable for their ability to fix nitrogen from the air into the soil through a symbiotic relationship with bacteria. Nitrogen is necessary for plants to thrive. This is why legumes are often used in crop rotation with grains like corn. Corn (and other grains – wheat, rye, barley, spelt, kamut, rice, etc.) completely depletes the soil and gives nothing in return. Legumes replenish the soil with nitrogen and reduce fertilizer costs for agricultural farmers.

Nutritionally, legumes are known to contain protein, minerals, and fiber. Legumes are rich sources of folate, magnesium, manganese, potassium, and iron, among other minerals. Cup for cup, legumes blow grains out of the water in fiber content. Thus far, everything about legumes sounds great! So why in the world would we want to avoid them? A few reasons that have everything to do with antinutrients.


Legumes contain antinutrients that prevent nutrient absorption and act as defense mechanisms to ward off biological predators. To understand this, place yourself in the “mind” of the plant. A fruit tree wants nothing more than for you to eat its fruit and poop out the seeds and fertilizer somewhere habitable for a new fruit tree. Legumes (and grains, for that matter) are NOT fruit. They do not want to be eaten because it means the end of their species. In addition, predator-prey relationships exist in the plant world too. Legumes contain substances that protect them from predators like fungi and bacteria or herbivores. These substances are either toxic, benign or beneficial in humans, but many are toxic. Thus, they are called antinutrients and lower the nutritional value of food through their action in the body.

Effects of antinutrients in humans range from DNA damage to full blown immune responses. A few specific antinutrients are worth noting:

Protease Inhibitors

These proteins are capable of inhibiting enzymes that break down protein. In legumes, protease inhibitors act to defend the seeds from being eaten by a predator. One of the most well studied protease inhibitors from the plant world inhibits trypsin and chymotrypsin, gastric juices secreted by the pancreas into the digestive tract. Because protease inhibitors are relatively stable, they survive passage through the stomach. Effects of protease inhibitors include an enlarged pancreas and/or uncontrolled growth of pancreatic cells in rats, which may lead to cancer.


These antinutrients are proteins that are present in every plant and animal, but in toxic concentrations in legumes. Lectins have the unique ability of sticking to sugar-compounds. WGA (wheat germ agglutinin), the large protein that contains gluten, is a lectin familiar to most people. Legumes contain similar molecules specific to the species of plant.

Lectins are dangerous because they are not digested and pass into the gut (a.k.a. intestines), they influence harmful shifts in bacterial flora, and interfere with nutrient absorption capabilities.

After food is broken down into individual proteins, fats, minerals, sugars, and vitamins, the gut is where nutrients are absorbed, gaining passage out of the intestines and into the body. The gut is very picky about what it allows through the gut lining, but sometimes harmful molecules like lectins look like safe nutrients and thus gain passage into the body. Because lectins are large molecules and the gut is not designed to allow them passage, they damage the gut lining and pave the way for other unwelcome proteins and molecules to travel through the gut into the body.

Because the gut is an entry point of viruses and bacterial infections, the immune system is always on high alert and ready to put down any threat that enters the body. It does this by producing antibodies specific to the foreign invader. The immune system pretty much grows an army that can specifically attack and destroy the unwelcome foreign invader. Remember that lectins look like safe nutrients because they stick to sugars and gain entry into the body. When the immune system attacks the foreign invader, it also attacks whatever it is stuck to, i.e. normal body tissues. What this means is that if lectins stick to cells in your pancreas and your immune system continually attacks those lectins, then your pancreas can cease to function and you are diagnosed with type I diabetes.

Kidney bean lectins have demonstrated the ability decrease circulating insulin levels, thus affecting the delicate hormonal balance, in rats. And the subtle influence of chronic intake of WGA has been demonstrated to stunt growth in children with celiac, affect metabolism, and deteriorate health.

Lectins are a big deal. Because they damage the intestinal lining and allow other unwelcome substances (i.e. the contents of your intestines) a wide doorway into the body, lectins pave the way for food allergies, autoimmune conditions and multiple chemical sensitivities syndrome. Lectins have also been demonstrated to affect the enzyme transglutaminase (TG). This enzyme alters every protein in our body. That’s right, every single one. This includes proteins in the brain, heart, lungs, liver, kidneys, reproductive organs, and pancreas. What this means is that lectins can single-handedly damage every organ and tissue in our bodies and appear to be a causative factor in several conditions like Huntington’s, infertility, rheumatoid arthritis, and multiple sclerosis, just to name a few.

Lectins are found in especially high concentrations in soy.

Phytate & Polyphenols

Phytate/Phytic acid is a compound that absorbs nitrogen in plants. In humans, phytate present in legumes considered an antinutrient because it interferes with the absorption of iron, zinc and calcium. You see, just because a food contains x, y, z beneficial nutrients does not mean that our body absorbs and uses x, y, x nutrients. That is the main reason why women are recommended to take such high doses of calcium on the predominately dairy, legume, & grain-based diets of western cultures. The idea is that if you overload the system, you might absorb enough calcium to balance out the calcium your body leaches out in the presence of these foods. In the paper I read, phytates were present in the highest concentrations in red kidney beans and soy and in lower concentrations in peas and lentils.

Polyphenols are another antinutrient found in legumes that prevent the absorption of iron. Polyphenols are found in higher concentrations in colored legume seeds like beans and in lower concentrations in peas.

The good news is that some food processing techniques are able to decrease phytate content and increase nutrient bioavailability in legumes. Traditional soaking techniques, fermentation and sprouting are some ways to naturally increase phytase, the enzyme that breaks down phytate, in legumes. Heating, however, destroys phytase. Vitamin C, present in high doses in fruit (especially citrus), is also known to enhance iron absorption thus canceling out the iron-absorption inhibiting effects of phytates.

The Bottom-Line

As you can see, antinutrients negate any potential benefits of the foods in which they are present in high doses. Because legumes contain a significant amount of antinutrients, Paleo recommends against legumes as a staple of your diet, especially for the first 30 days.

Legumes are also difficult to digest by the bacterial flora in our gut. This usually presents itself by bloating, gas, and/or pain.

Everyone’s body is different. We each have varying degrees of immune system health and gut health. This means different levels of tolerance for certain foods. After your first 30 days on Paleo, you may re-introduce foods, like legumes, to see if your body tolerates them. I recommend doing this one at a time, and only once every few days. This will give you a more accurate picture of the offending food if you experience gastrointestinal issues or pain.

There is no way to tell who will tolerate which legume better than another, but generally, most people tolerate peas and green beans well and have more issues with beans, peanuts and soy. I highly recommend against soy as a staple of your diet ever.

In Conclusion…

The inaugural article of Why Wednesdays examines the why behind the “No Legume” recommendation of the Paleo diet. Although legumes are nutrient-dense, they also contain an inordinate amount of antinutrients that negate any potential benefits of legumes. Unlike fruit, legumes do not want to be eaten by humans or animals and thus contain substances, like lectins, to ward off predators by causing damage to those that do eat them. Some antinutrients in legumes include protease inhibitors, lectins, phytates and polyphenols. These antinutrients vary in their degree of harm, but all interfere with nutrient absorption, digestion, and gut health. Lectins are the most studied and are the most dangerous because of their ability to tear holes in the intestines and illicit immune responses against resident body tissues, causing autoimmune conditions and severe damage to one’s health. While Paleo recommends against making legumes a staple of your diet, people vary in their ability to tolerate legumes. It is okay to reintroduce legumes in small doses after the first 30 days. Most people seem to tolerate peas and green beans well, while beans, peanuts and soy are more problematic.


Sources/Recommended Reading:

Photo Credit: www.fullissue.com


What do you think? Does this give you a better understanding of legumes and why they may not be the greatest ever, though they are delightfully tasty sometimes 😉 ?! Comment below.

If you liked this post, please share it with your friends, family or co-workers because it could help them transform their lives and experience relief. I spent about 4 hours researching and writing this article, so I hope it has provided clarity and is beneficial to you.


  • Laura

    Reply Reply July 6, 2011

    Thanks, gerilyn! Very Informative. I have a hard time tolerating legumes, myself…

    • gerilyn

      Reply Reply July 6, 2011

      Sure, Laura! Hope this helps! I know you were asking about it recently and I, too, have wondered at times. I’ll do an article on different traditional soaking, fermenting and sprouting methods in the future that may help if you wanted to try legumes again…

  • joyce

    Reply Reply July 6, 2011

    And all this time I thought legumes were my friends! Thank you for all your time and work in researching this topic. It is very informative and answers some questions that I had.

    • gerilyn

      Reply Reply July 6, 2011

      Hi Joyce! I love legumes too. And you better believe I still eat them when I want (you sure can’t beat white beans and corn bread! :)… BUT they are not a staple of my diet, i.e., I’m not eating them 2-3 times per day. I’m going to experiment with the traditional methods of legume preparation – soaking, fermentation and sprouting – and will do a post on it in the future. I appreciate your support.

  • Mike

    Reply Reply July 7, 2011

    So, I’m guessing chili dogs are pretty much ok, right…just kidding…I don’t eat beans everyday, but I will definitely have to watch out on these sneaky legumes. I have switched to Almond butter instead of peanut butter and I actually think I like it better sometimes…

    • gerilyn

      Reply Reply July 7, 2011

      Ha ha! I wish! 🙂 My favorite meal at Sonic used to be a chili dog with no dog… go figure. Mmmmmm, almond butter. Love it. We’ve started getting Justin’s Nut Butters in to-go packs for snacks at work or on a busy day when we do not have time to eat. They are delicious!

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