Are Beans and Legumes Bad?

Recently, a friend posted this on my Facebook page:

What’s up with legumes? Good/bad? What is the “right” amount? A lot of my friends are on the Whole30 kick and I’m personally trying to add a variety of protein sources to my boys’ diet. Then I saw Whole30 doesn’t allow legumes. Do you have a resource you could steer me to? It’s tough sometimes navigating all the “this is good, this is bad” stuff out there.

This is why I write my blog, and this is why I love being a Registered Dietitian! My friend is right, it's hard to navigate all the information out there. It's hard to know what is truth, what is sensationalized, and what is just garbage.

As I answer this question, let me be upfront and say that I'm not a huge fan of the Paleo diet. I touched on this in an earlier post and love this 5-minute video by My biggest concern is the way Paleo and Whole30 eliminate entire food groups. It's highly restrictive, cuts out healthy foods, and can set you up for nutritional deficiencies and disordered eating. To be fair, there are some good things about Paleo, but I'm still not won over! Let’s look at both sides.

What are the arguments against beans?

Gas, Bloating, Discomfort

This is not a nutritional argument, but it certainly is one that I hear clients use! Your body is an amazingly adaptive machine that wants to be efficient. It learns about your habits and patterns and responds accordingly. Your body will get used to it - the more often you eat beans, the better your body can handle them. The problem is when you shock your system with "new" foods. Note: this same thing happens with junk food, but for some reason, we're more willing to persevere on that front. Ha!

Try incorporating beans consistently to your diet - even in small doses - and you'll notice your body will begin to respond better. You can also consider taking Beano(R) or something similar. If you're using canned beans, be sure to drain and rinse them first. You'll not only save yourself tons of sodium (about 40% is removed when you rinse and drain), but some of that gas, as well. For a more extensive look at this topic, a piece from the Savvy Vegetarian.

Phytic Acid / Phytates

The major argument against beans and legumes is that they contain phytic acid or phytates (the suffixes "-ic acid" and "-ate" are two different ways of naming the same chemical structure). Why is this so atrocious? Phytic acid is sometimes referred to as an “anti-nutrient” because it binds to minerals in your digestive tract, preventing them from being absorbed. That means while you might see ½-cup serving of beans contains about 2-3mg of iron, your body may not actually absorb that much? It will definitively not absorb all of it, due to the presence of the phytic acid. But it is unclear how much is actually lost.

The Paleo and Whole30 crowd would say that this is the reason to avoid beans and legumes. They believe that you are creating nutrient deficiencies by consuming these foods. The issue, they say, lies in the quantity in which people consume beans and legumes. Nuts and seeds also contain phytates, but they are consumed by the tablespoon, not the cup.

I say, don't throw out the baby with the bath water.

First, when the recommended daily intakes for nutrients were established, phytic acid was taken into account. So even though we might not get all of the nutrients naturally found in foods, you don’t have to be concern about a nutrient deficiency occurring. I would also push back and say the average American doesn’t meet the recommended amount of beans (3 cups/week), so this is a bit of a moot point.

Second, when phytic acid binds to minerals in the gut, it prevents the formation of free radicals. Instead of an “anti-nutrient”, this actually makes it an antioxidant with anti-disease properties. Additionally, phytic acid can bind to heavy metals, preventing accumulation and intoxication in the body.

Finally, there are ways around this "anti-nutrient" aspect of phytic acid. Various methods of preparation will reduce the amount of phytic acid in foods. Sprouting, soaking or fermenting, along with adding heat can make a difference. Pairing phytate-rich foods with foods high in vitamin C or vinegar will aid in mineral absorption and offset the phytic acid.

What is my argument FOR beans?

Nutrient Density

Beans pack a lot of nutrition. Specifically, they are a great source of:

  • fiber

  • potassium

  • magnesium

  • iron

  • B vitamins

  • antioxidants

  • other phytonutrients

  • plant-based protein

These are all nutrients that Americans are either not getting enough of or nutrients they are actively trying to get more of. Seriously, how trendy is plant-based protein right now?!

Disease Prevention

Photo by  Deryn Macey  on  Unsplash

Photo by Deryn Macey on Unsplash

Beans are associated with lower disease risk. Specifically, beans are associated with lower cholesterol levels and less heart attacks. A study in the Canadian Medical Journal found that eating a daily serving of beans, peas, chickpeas, or lentils can decrease levels of LDL cholesterol by 5%, as well as reducing the incidence of cardiovascular disease by 5-6%. 

In addition, the researchers in a study in the British Medical Journal found that an additional 7g of fiber daily could reduce the risk of heart disease by 9%. The potassium and magnesium in the beans also help prevent disease. Potassium naturally helps remove excess sodium, which helps reduce blood pressure. Magnesium also plays a role in reducing blood pressure.

There is also some evidence that eating beans can prevent cancer. Specifically, the International Journal of Cancer found an association between beans and lentil consumption and a reduced risk of breast cancer. Another study in The Journal of Cancer Research associated legume consumption with a lower rate of colorectal polyps - a precursor to colon and rectal cancers.


In my world, the benefits of beans far outweigh the potential negatives. The Dietary Guidelines for Americans recommend 3 cups of beans each week. Which, if we circle back to the phytate issue, isn't really all that much. Just don't eat all 3 cups at one time! Getting in ½-cup serving per day doesn't have to be hard. Here are a few recipes to get you started.

Black Bean Salad with Quinoa and Avocado by Whitney English, RD

Vegan Pumpkin Chili by Alex Caspero, RD

Crispy Chile Lime Roasted Chickpeas by The Domestic Dietitian

Black Bean Brownies by Chocolate Covered Katie

Lentil Sausage Soup by Whole Foods Market

Roasted Beet and White Bean Power Bowl by 80twenty Nutrition (pictured below)

roasted beet and white bean power bowl