FanHouse

Tomorrow is the Fourth of July, which means one of America's great annual sporting events -- the Nathan's Famous Hot Dog Eating Contest -- will take place on Coney Island.

The typical reaction from people who watch competitive eating is that it seems impossible that the human digestive system can handle the stress of getting 60-plus hot dogs shoved into it in a 12-minute span. So how do they do it? The Wall Street Journal's Health Blog reports that a study published last year in the Journal of Roentgenology, titled, "Competitive Speed Eating: Truth and Consequences," provides an answer by observing a competitive eater stuffing his face.:

"His stomach now appeared as a massively distended, foodfilled sac occupying most of the upper abdomen, with little or no gastric peristalsis." [Marc Levine, a radiologist at the University of Pennsylvania] said the stomach was like no healthy stomach he'd seen in his 30-year career. He compared it to a "giant balloon that looks like it has no limit." The eater's previously flat belly swelled out as if he were pregnant.

So that's the bottom line. A normal person's stomach doesn't stretch much when food is put into it, and that's why we feel full. The stomachs of guys like Joey Chestnut and Kobayashi just keep expanding.