Why Do Beans Make You Fart? Here's What a Dietitian Has to Say (2024)

We've all heard the childhood rhyme that starts with "beans, beans, the magical fruit," but what happens when that "magic" leaves you feeling uncomfortable and embarrassed? Many people experience gas and bloating after eating beans, but few know why.

Here, we'll examine why beans make you fart and how to prevent gas and bloating from these nutritious legumes. We'll cover the science behind the link between beans and gas and provide tips for enjoying beans without the smelly side effects.

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What's the Link Between Beans and Gas?

Beans are a staple in many healthy diets (and it's no wonder, considering they're an excellent source of protein, fiber and nutrients). However, many people experience flatulence or gas after eating beans, and it can be a source of embarrassment and discomfort. So why do beans make you fart?

The answer lies in the complex carbohydrates found in beans that can be difficult for the body to digest. Specifically, beans contain a type of carbohydrate called oligosaccharides, more specifically raffinose, which, according to a 2022 review published in Frontiers in Plant Science, aren't easily broken down in the small intestine. Instead, they travel to the large intestine, where they're fermented by bacteria, producing gas as a byproduct. This gas must be released through belching or farting, which can be uncomfortable and unpleasant.

Kelsey Kunik, RDN, a registered dietitian nutritionist and nutrition advisor for Zenmaster Wellness, tells EatingWell, "Raffinose is a complex sugar that acts as a prebiotic in the digestive tract, increasing the number of good bacteria there. As bacteria break down the raffinose, several gases are released, which can lead to particularly smelly gas."

3 Reasons Why Beans May Make You Gassy

1. They Are High in Complex Carbs

Beans contain oligosaccharides, a type of complex carbohydrate that humans can't digest on their own. When these carbohydrates reach the large intestine, the bacteria in the gut break them down and produce gas as a byproduct. This is why eating beans can cause flatulence.

2. They Are Rich in Fiber

Beans are high in fiber, making them excellent for digestive health. However, too much fiber can cause bloating and gas.

"Beans are high in fiber, with half a cup providing between 4 and 8 grams," says Kunik. "Since your body can't digest fiber, it can sit in the digestive tract while the bacteria digest it, producing gas as a byproduct. This often happens if you eat too much fiber or increase your fiber intake too quickly without allowing your body time to adjust."

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3. They Are High in Lectins

Lectins are proteins found in plants that bind to carbohydrates and are difficult to digest. And according to a 2021 article in Foods, legumes are rich in lectins. Some individuals may be more sensitive to lectins and could experience gastrointestinal discomfort when consuming lectin-rich foods like beans.

How to Prevent Gas and Bloating from Beans

If you're a fan of beans but experience uncomfortable gastrointestinal side effects when you eat them, you can prevent or minimize these symptoms in a few ways.

  • Soak your beans: Soaking beans before cooking them can reduce the amount of oligosaccharides. Simply place your beans in a large bowl and cover them with water to soak them. Let them soak overnight before draining and cooking them. "To reduce the gas caused by eating beans, you can either soak them before eating them, which helps to draw out some of the gas-producing sugars, or cook them with kombu, a seaweed that contains the enzyme glutamic acid that helps to break down raffinose," says Kunik.
  • Add digestive aids: Certain herbs and spices can aid digestion and reduce the risk of gas and bloating. For example, add ginger, fennel seeds, cumin or coriander to your bean dishes. These herbs and spices can help to stimulate digestive enzymes and reduce inflammation in the gut.
  • Start slowly and build up: If you're not used to eating beans, it's best to start slowly and gradually build up your intake. Start with small portions of cooked beans and gradually increase the amount over time. According to the National Institutes of Health, this will allow your body to adjust to the increased fiber and complex carbs in the beans and reduce the risk of gas and bloating.

The Bottom Line

Beans are a nutritious food packed with essential nutrients, but they can also cause gas and bloating due to their high fiber content. In addition, beans contain oligosaccharides, which are not easily digested in the small intestine and are fermented by bacteria in the large intestine, producing gas. Fortunately, there are ways to reduce the risk of experiencing gas from eating beans, such as soaking them before cooking, eating smaller portions and gradually increasing your intake. By following these tips, you can keep enjoying the many health benefits of beans without experiencing the unpleasant side effects.

Read Next: 4 Foods You Should Eat If You Want Less-Smelly Farts

Frequently Asked Questions

  • How do you stop beans from giving you gas?

    Soak dried beans for at least eight hours or overnight before cooking to reduce the number of indigestible sugars which cause gas. Rinse canned beans thoroughly and consider adding foods naturally high in digestive enzymes in your cooking to aid digestion.

  • Which beans make you fart the most?

    While any legume has the potential to cause gas, certain varieties are notorious for their gassiness. "Soybeans, pinto beans, black beans and lentils are most likely to cause gas because of the amount of fermentable sugars and fiber," says Kunik.

  • Why do beans give you smelly gas?

    Beans contain complex sugars called oligosaccharides that are difficult for the body to break down. As a result, gas is produced when bacteria in the large intestine feed on these sugars. Additionally, sulfur-containing compounds in beans can contribute to the unpleasant odor of flatulence.

    "The odor produced after eating beans is different (and often smellier) than gas from other sources," states Kunik. "This is because of the specific types of gas given off as the bacteria in the colon digest the sugars found in beans."

Why Do Beans Make You Fart? Here's What a Dietitian Has to Say (2024)

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