For today’s edition of Dear Mark, I’m answering a reader question about beans. But it’s not just about beans. It’s about something called the Bean Protocol, a rather new dietary approach that many of my readers have expressed interest in. The Bean Protocol is supposed to improve the liver’s ability to clear out toxins, thereby preventing them from recirculating throughout the body in perpetuity. Today, I’m going to discuss where it fits in a Primal eating plan.
Have you heard about this “Bean Protocol”? From what I can tell people are eating tons of beans and getting great results. It’s supposed to remove toxins from the liver or something else that only beans can do.
What do you think?
I did some digging around. I read the Bean Protocol coverage over at PaleOMG, where Juli has been following the bean protocol for several months now and seeing great results. There’s a Bean Protocol E-course that I did not sign up for, but I think I have a decent handle on the topic.
How to Do the Bean Protocol
Here’s the gist:
No processed food
No factory-farmed meats; no fatty meats
Eat 3 half-cup servings of beans or lentils a day (varies by person)
Fill the rest of the food with lean meat, leafy green vegetables, alliums (onion, garlic, leek, etc), and cruciferous vegetables (broccoli, cabbage, cauliflower).
What’s Supposed to Happen on the Bean Protocol
The soluble and insoluble fiber in the beans binds to toxins which the body can then flush out more easily. Without the fiber from the beans, your body can’t process and excrete the toxins, so they simply recirculate, stay in the body, and sometimes express themselves in the form of acne and other diseases. Adherents credit the bean protocol for fixing longstanding issues like acne, Crohn’s, and many other conditions.
Is this true? Is there any evidence of this in the scientific literature?
Well, there isn’t much direct evidence for beans improving liver clearance of toxins, but there is circumstantial evidence. For one, prebiotic fiber is good for liver health. There are plenty of studies to support this.
Synbiotics (a combination of probiotics and prebiotics) and BCAAs taken together improve hepatic encephalopathy, a feature of liver failure where the liver fails to detoxify excess ammonia.1 However, it does not do so directly. The fiber isn’t necessarily “binding” to the lead and excreting it. Instead, it does so by increasing levels of lead-binding gut bacteria which in turn bind and excrete it, shoring up the gut lining so that lead can’t make it into circulation, increasing bile acid flow, and increasing the utilization of healthy essential metals (like zinc and iron). The bacteria are essential for the effect; pre-treatment with antibiotics abolishes the benefits. So we can’t say for sure that the fiber itself is “binding” to the toxins.
The Bean Protocol is also rich in allium vegetables like garlic and onions, another source of prebiotic fibers shown to improve liver health and toxin clearance. For instance, inulin given to rats prevents acute cadmium toxicity.2 Inulin also increases bile flow.3 Moreover, compounds found in garlic improve glutathione activity in the liver and enhance its ability to metabolize toxins.4
The Bean Protocol also emphasizes cruciferous vegetable consumption. The crucifers, which include cabbage, broccoli, cauliflower, and kale, can exert beneficial effects on liver health. Sulforaphane, one of the most prominent compounds in cruciferous vegetables, has well-established effects on toxin clearance. It can speed up the clearance of airborne pollutants and counter the carcinogens formed from high-heat cooking.56
Back to Basics
By emphasizing lean meats and eliminating sugar, alcohol, and industrial food, you are eliminating the major causes of fatty liver in the diet: sugar, seed oils, and alcohol.
My point is not to disparage the Bean Protocol. I think it has some merit. My point is to point out that beans alone probably don’t explain the benefits people are seeing. There’s a lot more going on than just beans.
Lectins and Phytic Acid in Beans
Okay, okay. So while beans aren’t the only (or even necessarily the best) way to obtain prebiotic fiber to modulate gut bacteria and improve liver health and therefore toxin clearance and metabolism, they are promising. But aren’t beans bad for you? Aren’t they neolithic foods full of lectins and anti-nutrients that are anything but Primal?
Lectins are anti-nutrients and beans do have them. Studies show that they can damage the intestinal lining, prey upon already-damaged intestinal lining, and prevent the body from repairing that damage.7 If they make it into the bloodstream, they can bind to cell membranes throughout the body, trigger autoimmune reactions, and cause real havoc.8 People have actually been hospitalized from lectin poisoning.9
But here’s the thing: cooking and soaking deactivates the majority of legume lectins.
In one study, navy and kidney beans showed 0.1% lectins leftover after cooking.10
One study found that pressure cooking kidney beans for 30 minutes eliminated all hemagglutinin activity.11
In another, a combo of soaking and cooking white beans completely eliminated activity of the most pernicious lectin, the one responsible for kidney bean poisoning: phytohemagglutinin.12
Most of the research indicting legume lectins used animals consuming large amounts of raw lectins. Those people who got lectin poisoning ate undercooked kidney beans. Don’t eat raw or undercooked beans and make sure they’re soaked overnight. Canned beans are also prepared pretty well.
Okay, what about phytic acid?
Phytic acid is the primary storage form of phosphorus in plants. When you eat a food containing phytic acid, it can bind to several other minerals, like calcium, magnesium, and zinc, and prevent their absorption. Diets based entirely in high-phytate foods can thereby lead to nutrient deficiencies. As legumes are one such high-phytate food, people are justifiably cautious about basing their diet on them.
Soaking legumes is really good at reducing phytic acid. In one study, cooking straight up without soaking reduced phytate by 20%, cooking after soaking in the soaking water reduced it by 53%, and cooking after soaking in fresh water reduced it by 60%.13 Another study found that cooking in fresh water after 16 hours of soaking with a 3:1 water:bean ratio eliminated 85% of phytate.14 That basically takes care of the problem.
Consuming phytic acid can also be cancer-protective in some instances.15
If you want to really eliminate phytic acid you can sprout your legumes. You can also buy pre-sprouted beans.
What about the carb content of beans?
Legumes are higher in carbs than many other Primal foods but not as high as you might think. The musicality of the legume partially offsets its carbohydrate density. All those sugars and fibers being digested by gut bugs and producing the farts are carbs that you aren’t consuming as glucose. If you pay attention to “net carbs,” you’ll love legumes—at least compared to something like potatoes or bread.
Which, by the way, is why legumes appear to be so helpful in the Bean Protocol.
A half cup of cooked black beans has 20 grams of carbs with 7.5 coming from fiber.
A half cup of cooked chickpeas has 30 grams of carbs with 5 coming from fiber.
A half cup of cooked pinto beans has 22 grams of carbs with 7.7 coming from fiber.
A half cup of cooked lentils has 20 grams of carbs with 7.8 coming from fiber.
And much of that fiber, remember, comes in the form of galactooligosaccharides, that same prebiotic shown in studies to improve gut health and even increase lead excretion. But these are also FODMAPs, which, depending on your gut biome, can be helpful or painful. Some people won’t be able to handle the gas, some will get downright painful bloating, while others will get huge prebiotic benefits. Your mileage may vary, so just figure out what works.
Are beans actually nutritious, though?
Legumes aren’t nutrient-dense compared to something like liver or oysters, but they’re more nutrient-dense than grains and many other foods.
Again, a half cup of beans isn’t very many carbs. Maybe 20 grams, with only two thirds of that turning into glucose. You’ll get a lot of food for your gut and a decent whack of some important nutrients like folate, copper, magnesium, and manganese. That half cup of black beans provides 32% of your daily folate requirements, 20% of copper, 14% of magnesium, and 17% of manganese. A half cup of lentils provides 45% of your daily folate requirements along with 28% of copper and 21% of manganese. Not bad for a measly 20 grams of carbs.
A Plea: Lentils
If you want to try the Bean Protocol and insist on doing the 8 servings a day version, I’d recommend you go with lentils.
A cup of standard lentils gets you:
40 grams carbs, almost 16 g fiber.
18 grams protein. Legume protein can’t replace animal protein, but it can offset some of your requirements.
90% of folate.
28% of vitamin B1 (thiamine), 25% of vitamin B5 (pantothenic acid), and 21% of B6 (pyridoxine). B vitamins generally aren’t issues for folks eating Primal, but they can’t hurt.
55% of copper.
17% of magnesium.
43% of manganese.
Lentils added to a meal slow gastric emptying, which should keep a person fuller longer.16 This is in contrast to most sources of refined carbs, which increase a person’s hunger.
Another benefit is that lentil prep is simple. They contain less phytic acid than most other legumes and require less soaking (or none at all) and cooking time than other legumes to reduce it. If you want to sprout lentils, they sprout much quicker than beans.
All in all, I’d say the Bean Protocol is worth trying if you’re interested or intrigued. I don’t know that the “8 servings of beans” is more important than the other stuff you’re eating or omitting, but I also know that sometimes things just work a certain way even if the hard clinical evidence hasn’t been established. After all, people used to say the same thing about Primal or keto.
If you do try out the Bean Protocol, be sure to keep us all informed and up to date on your progress. I’d be really curious to hear about it.
What about the supposed ability of fiber to bind and excrete toxins? That’s ultimately what it all comes down to. It’s the central tenet of the bean protocol. Let’s explore the evidence.
Beans are a rich source of galacto-oligosaccharides, a type of prebiotic fiber. In mice, galacto-oligosaccharide supplementation increases excretion of lead, a veritable heavy metal toxin.[ref]https://pubmed.ncbi.nlm.nih.gov/31180403/
Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.