OK—Why Do Beans Make You Fart? RDs Spill

You know how the playground rhyme goes, so we won't go there. However, have you ever wondered what the "why" behind it was? As in, why do beans make you fart?

The question might make you blush, which is why you're here, probably via a Google search rather than saving it for your next trip to your primary care doctor or dietitian. Yet, the answer is rather important. Understanding how food affects the body—and your body in particular—can help you make empowered choices. Also, beans not only cause gas but can also lead to another issue that isn't just embarrassing but uncomfortable.

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"Bloating is a very common complaint and can lead to a lot of discomfort throughout the day," says Lisa Moskovitz, RD, the CEO of NY Nutrition Group and author of The Core 3 Healthy Eating Plan. "While the root cause of bloating varies from person to person, certain foods can make it worse or better."

Beans fit that bill, but why? We did the dirty work, asking dietitians, "Why do beans cause gas?" and "Which beans make you fart the most?" so you don't have to. They also shared ways to enjoy beans while avoiding the social faux pas (albeit a natural occurrence that happens to the best of us) of passing gas in public.

Related: These Are the 6 Healthiest Beans and Legumes You Can Eat, According to Dietitians

Do Beans Make You Fart?

Beans can absolutely make you fart. So, the better question is, "Why do beans make you fart?" It comes down to one of the most beneficial features of eating beans: Fiber. Beans contain a type of fiber called raffinose, a non-digestible oligosaccharide that is a good-for-the-gut prebiotic. OK, but if it's so good for the gut, why raffinose cause gas? The answer will help you understand that it's biologically normal for beans to cause gas.

"When we eat beans, the unique fiber they contain barely get broken down in the stomach and small intestine, like foods typically do," explains Destini Moody, RD, LD, CSSD, a registered dietitian with Garage Gym Reviews. "Instead, they end up in the large intestine. The problem is, the large intestine contains no digestive enzymes to help break these foods down, so our intestinal bacteria ferment it instead, producing gas in the process."

Now, the fiber beans contain is a good thing. Beans are also an excellent source of plant-based protein. Combined with whole grains like brown rice or whole wheat pasta, beans help your body get all the amino acids it needs to thrive. Therefore, experts don't recommend most people skip beans because of fart fears.

"This isn't a reason to avoid this nutrient-dense food," says Dr. Chris Mohr, Ph.D., RD, a fitness and nutrition advisor for Fortune Recommends Health. "As the body gets used to more regular consumption and this higher amount of fiber, these symptoms usually subside."

Related: 22 High-Fiber Lunch Ideas That Will Help You Beat the 4 p.m. Slump

Why Do Beans Cause Gas? 5 Potential Reasons

1. Beans contain raffinose

Like many plant-based foods, including asparagus and broccoli, beans contain something called called raffinose. It's a type of carbohydrate known as an oligosaccharide that acts as a prebiotic.

"Our body’s digestive system doesn’t always break down this type of sugar very efficiently because we do not have an enzyme that breaks down raffinose," Moody says. "So, this leaves it to the bacteria in our gut to do the heavy lifting. When bacteria break down fibers in our gut, they release gas and, well, that gas has to go somewhere."

Preparation can affect how many oligosaccharides you consume when eating beans.

"Dry beans that are not adequately soaked or cooked can retain higher levels of oligosaccharides and be more difficult to digest, leading to increased bloating and gas," Dr. Mohr says.

2.  They are high in fiber

Beans are an excellent source of fiber, which helps you stay fuller longer. That's good news, but fiber can make you gassy, especially if you consume a ton at once or aren't used to eating it (many people don't get enough fiber, studies show).

"Some legumes are roughly 10% fiber by weight and the type of fiber they contain can cause gas, especially if you are not used to eating a high-fiber diet," Moody says. "If you typically do not consume a lot of fiber, the GI tract may react to high-fiber foods with gas and constipation."

3. Beans have lectins

As a plant-based protein, beans are packed with lectins, per an article in Foods published in 2021.

"Lectins are a type of protein that are very common in plant foods including whole grains and peanuts, which are also in the legume family," Moody says. "Given that beans are a good source of protein, they are particularly high in lectins. The gas produced during the digestion of lectins can cause bloating."

4. You're eating them too quickly

"Eating beans too quickly can lead to swallowing excess air, which accumulates in the digestive tract and exacerbates bloating and gas," Dr. Mohr says.

While this is true of any food, when you combine gobbling up beans with their high-fiber, high-lectin content, it's a recipe for gas and bloating.

5. You have a condition/intolerance

Our body's abilities to digest and tolerate foods can vary, especially if you have specific conditions.

"Certain conditions like small intestinal bacterial overgrowth can cause a great deal of bloating due to dysbiosis in the gut, among other uncomfortable GI side effects," Moskovitz explains. "Food intolerances or sensitivities can also contribute to gastrointestinal issues, and the first sign is usually a distended tummy."

Preventing Gas and Bloating From Beans

1. Soak beans well

As with so many aspects of life, preparation is key. "Soaking dry beans in water for several hours before cooking them can reduce the potential for them to cause gas and bloating by releasing some of the non-digestible, fermentable fibers into the water," says Melissa Buscetta, RD, a registered dietitian at Fay.

2. Spice up your beans

Besides soaking, adding certain ingredients to beans might help lower how much, uh, cheese you cut after eating them.

"Adding spices known for their digestive properties, like ginger, turmeric or fennel, can help mitigate bloating and enhance the overall digestion of beans," Dr. Mohr says.

3. Go easy on intake

Avoid trying to get your entire daily fiber fix in one gigantic serving of beans.

"Sometimes, it’s not the type of fiber, but the amount of fiber you are eating that can cause some gassy issues," Moody says. "If you are not used to eating beans or high-fiber foods in general, start out with small portions at first. Then, gradually and consistently increase your intake to allow your GI tract to adjust properly."

4. Eat slow

Speaking of slow, avoid speed eating. Yes, you're busy, but you deserve time to eat. Consider it delayed gratification for you and the people around you who are pressuring you to "be more productive."

"Eat slowly and make sure you're breathing properly before, during and after the meal," Moskovitz says.

If hustle culture allows: Go for a little walk and stretch after meals to help circulate air through your GI tract," Moskovitz adds.

5. Get checked out

While some gas and bloating are a natural part of post-bean consumption, there's such a thing as too much of it.

"If bloating is chronic, it is important to seek medical attention to further evaluate potential causes of bloating," Buscetta says.

OK, But Which Beans Make You Fart The Most?

"All beans such as red kidney, black, soy and lima beans tend to have a high soluble fiber content, and more fermentable carbohydrates make them harder to digest," Buscetta says. Yet, your (gas) mileage may vary.

"Over the years of counseling individuals, I have found that everyone is different, so it can be helpful to be your own little detective and keep a mental note or food journal on which foods cause you the most gastrointestinal discomfort," Buscetta says.

Up Next:

Related: The 2 Most Important Things Your Farts Reveal About Your Health, According to GI Docs

Sources:

• Lisa Moskovitz, RD, the CEO of NY Nutrition Group and author of The Core 3 Healthy Eating Plan

• Destini Moody, RD, LD, CSSD, a registered dietitian with Garage Gym Reviews

• Raffinose Family Oligosaccharides: Friend or Foe for Human and Plant Health? Frontiers in Science.

• Dr. Chris Mohr, Ph.D., RD, a fitness and nutrition advisor for Fortune Recommends Health

• Closing America’s Fiber Intake Gap. American Journal of Lifestyle Medicine.

• Lectin Activity in Commonly Consumed Plant-Based Foods: Calling for Method Harmonization and Risk Assessment. Foods.

• Melissa Buscetta, RD, a registered dietitian at Fay