Fiber may in some cases cause gas. Gas is a natural product of fermentation in the large intestine, so the amount of gas produced will depend on the fiber’s fermentation characteristics as well as each individuals health and other conditions. Most insoluble fibers won’t produce gas because they are not fermented. However, some people do experience flatulence when they eat more fermentable fiber than they are accustomed to consuming. With a diet rich in fermentable fiber, there may temporarily be an increase in gas, but the body eventually adapts. One tip to help reduce flatulence is to increase fiber intake gradually. If you are accustomed to a high fiber diet, you likely won’t notice any difference when you eat foods with added fiber.