Researchers from the Mayo Clinic found that on average the entire process from the time someone eats until the time they eliminate takes about 53 hours. However, the time it takes to digest food is not the same for various individuals and for men, women and children as groups.
After a person ingests food, it takes about six to eight hours to traverse the stomach and small intestine. Transit time through the large intestine, or colon, takes significantly longer, averaging about 40 hours. In men, the food remains in the colon about 33 hours, while in women it remains about 47 hours. When two British doctors researched digestion time in children, they found it was significantly more rapid than in adults, averaging just 33 hours from eating to elimination.