For about an hour after eating, the body focuses its energy on digesting the meal: the blood goes to the stomach, the energy supply dips, and the metabolism thinks food. But this has nothing to do with the dreaded “stomach cramps” that every mother warns her child about. There is no such thing as a stomach cramp. And there is no connection to a muscle cramp that may, indeed, endanger a swimmer. Most likely, Mom just doesn’;t want you to blow lunch.