Sometimes the magic time limit is given as thirty minutes. For some mean midcentury moms, it lasted up to two hours! In any case, the conventional wisdom was clear: kids drown when they hop back into the pool right after eating. These advisories date back at least to the 19th century, and were codified by the "Water Hints" section of the very first Boy Scout handbook, which sternly warned, "Many boy swimmers make the mistake of going into the water too soon after eating. The stomach and digestive organs are busy prepping the food for the blood and body. Suddenly they are called upon to care for the work of the swimmer. The change is too quick for the organs, the process of digestion stops, congestion is apt to follow, and then paralyzing cramps."
There are two true things in this passage: food is digested in the human abdomen, and abdominal cramps, if they hit while swimming, can be both painful and dangerous. But researchers have been telling us since the 1950s that there's no real connection between the two. Digestion just doesn't affect the body's oxygen usage or circulation enough to cause cramping. The American Red Cross publishes a 227-page (!) guide to water safety, and doesn't mention the dangers of post-meal swimming once. (There's a single paragraph about abdominal cramps, which calls them "rare" and attributes them to fatigue or cold, not overeating.)
If you've ever tried to exercise (or even climb a flight of stairs) after a big meal, you know it can be uncomfortable—but it's not immobilizing. There has never been a single water death attributed in the safety literature to a full tummy. So hop in the pool right after finishing your hot dog, kids. I'm your dad now, and I say it's okay.
Quick Quiz: The pioneering punk band The Cramps was associated with the scene at what legendary music club in New York's East Village?