Is it normal to have a bowel movement 12 hours after eating?

The time it takes for food to move through the digestive system varies from person to person. For some people, it may take as little as 12 hours, while for others it may take up to 72 hours. As long as you are having a bowel movement at least three times per week, you are considered to be regular and there is no need to be concerned. If you are having difficulty with constipation, there are a few things you can do to help improve your bowel movements, such as increasing your intake of fiber, drinking plenty of fluids, and exercising regularly.