Beans are high in soluble fiber, which is fermented by your gut bacteria, leading to increased gas production in the colon. Beans also contain a compound called raffinose.
The culprit is fiber. Beans are rich in dietary fiber, an insoluble carbohydrate. Although it is a carbohydrate, fiber is an oligosaccharide that your digestive tract doesn’t break down and use for energy, as it would simple sugars or starch.
One inquiry we ran across in our research was “Do beans cause gas when you eat them?”.
Beans, and other legumes like chickpeas, lentils and soybeans, are high in soluble fiber, which is considered beneficial for digestion. Unfortunately, it’s this soluble fiber that is also central to why they cause so much gas when you eat them.
To prevent gas that is caused by eating beans or other foods, the oligosaccharides must be broken down before they reach the large intestine and become food for the resident bacteria that live there. There is an enzyme that breaks down oligosaccharides, called alpha-galactosidase.
Another popular query is “Why do beans make you fart?”.
It is the bacteria in the intestine that finally breaks down these sugars. Doing so causes fermentation and the production of gas that we release as flatulence. By the same principle, other foods that come into the large intestine without being absorbed in the small intestine will cause gas.
What foods give you a lot of gas?
An April 2016 study published in the Iranian Red Crescent Medical Journal lists beans, lentils, fried and fatty foods, sour and spicy foods, coffee, tea, cocoa, ice and cold beverages as some of the foods that are likely to give you a lot of gas.
How are beans digested in the body?
Beans contain a complex sugar called raffinose that the body can’t fully digest. Normally, sugars like raffinose would be digested in the small intestine. However, since humans lack the enzyme to break it down, raffinose makes its way from the small into the large intestine still intact.