Quinoa contains 10 g of dietary fiber per cup. Considering that the average adult is recommended to consume between 20 and 35 g of fiber daily, one cup provides a substantial amount. If your body isn't accustomed to a lot of fiber in your diet, eating a lot of quinoa can lead to gas, bloating and stomach pain. Too much fiber can cause increased gas and abdominal pain because the bacteria in your colon isn't used to digesting the amount of fiber in quinoa. Avoid high fiber foods for a few days to see if your stomach pain subsides.