Well, our intestines can not digest everything we eat. Some leftovers are passed on to the colon. The colon is full of bacteria, yeasts and fungi. The processing or fermentation of leftover carbohydrates by the colonic bacteria leads to formation and being a major source of gas in your tummy. Composition of flatus varies among different people.
Many people feel that they pass too much gas.
Actually, there may not be any difference in amount of gas produced in complainers versus non-complainers. Just that, some folks are more sensitive and feel it more than others do. Just imagine, an average male passes gas 14 times per day. On rare occasions, patients may pass gas as many as 50-100 times per day. Elderly seem to pass more of it.