On the 240th anniversary of his country's independence, American Joey Chestnut ate 70 hot dogs in 10 minutes. A new record.
"Jaws," as Chestnut is known, put down a summer's worth of cased meats at the Nathan's Famous Hot Dog Eating Contest in 2016. It was an impressive physical accomplishment and a gargantuan intake of calories, fat and salt.
The competition, which started in 1916 and will be held again Tuesday, is a true gut-buster.
To stuff in that much meat and bun, competitors train their stomachs to expand, ruin their ability to feel full and risk long-term damage to their digestive systems.
How do they fit so much in?
The normal human stomach is about the size of a Nerf football, said Mayo Clinic gastroenterologist David Fleischer. At its biggest, it stretches about 15%.
On the other hand, competitive eaters can expand their stomachs two to three times their normal size.
Nobody knows for sure why people such as Chestnut and 2015 Nathan's champion Matt "The Megatoad" Stonie can pull this off, said Fleischer, who said he's a longtime Nathan's hot dog lover. Ivy League researchers suspect it's because competitive eaters train themselves to overcome the natural bodily triggers that tell us we're full.
A 2007 University of Pennsylvania study of one competitive eater found he changed his physiology to make himself an eating machine.
The study, published in the American Journal of Roentgenology, found the competitive eater's stomach expanded so "it could accept an almost unlimited volume of food."
"He was able to overcome the usual checks and balances associated with eating by exercising extraordinary willpower and self-discipline during his training, consuming more and more food when others wouldn't be able to swallow another bite without feeling sick," the study said.
Is there a 'grand expulsion'?
Not much has been written on what happens behind the bathroom door after an eating competition. It's best not to imagine it.
But gastroenterologist J. Sumner Bell suspects the process could take a long time.
"I don't know if there is a grand expulsion of this or not," said Bell, an expert for the American Gastroenterological Association. "If they don't self-induce vomiting, it may take a long time for it to be emptied from the stomach."
After eating, a normal person's stomach will return to its regular size in about an hour or two. The food exits the stomach into the small intestine to be absorbed for nutrients, then the colon and, well, you know the rest.
In a typical case, it takes somewhere between four and 24 hours for food to move from the stomach to a bowel movement.
Ingesting that much sodium could produce a lot of gas or diarrhea, Bell said. Electrolyte abnormalities caused by the gorge-fest could cause heart irregularities.
Why no weight gain?
Yet competitive eaters aren't the biggest among us. Chestnut, 33, is 6-foot-1 and 230 pounds while Stonie, 25, is just 5-foot-8 and 130 pounds.
Perhaps part of the reason is because most of the calories competitive eaters take in aren't absorbed by the body.
The small intestine recognizes when it doesn't need nutrients, Fleischer said. In the case of a big eating competition, most of the food, he said, exits the small intestine and is not absorbed.
In the University of Pennsylvania study, the competitive eater admitted he could no longer feel full and only stayed trim because he monitored how much he ate.
You could tear your stomach
Major League Eating, which oversees the Nathan's contest annually at New York's Coney Island, stresses it won't sanction or promote events that do not meet proper safety regulations.
The organization urges people not to try speed-eating at home, opposes home training and any eating for speed or quantity for any "younger individuals."
Fleischer agrees the sport should not be played at home because there is potential for injury, even if small.
There is a possibility, he said, that a person could stretch its stomach so much that it could tear. The same goes for the esophagus, Bell said
Voracious eating also could cause choking.
Despite the MLE's warnings, both Chestnut and Stonie admit to training. Stonie said he ate 60 hot dogs three days a week and would sometimes drink a gallon of water afterward to prepare for the hot dog eating contest.
Your stomach may never be the same
2016 Nathan's Hot Dog Eating Contest
The University of Pennsylvania researchers, in concluding their study, had some grim predictions for life after competitive eating, which they called a "potentially self-destructive form of behavior."
The researchers said the competitive eater, having lost the ability to feel full, could become obese.
Another possible issue is an eater could stretch their stomach so much that it no longer could contract and thus become unable to pass food. This condition, called gastroparesis, causes nausea and vomiting.
Bell suggests sticking to the basics this Fourth of July.
"A hot dog is a great American food, eaten one at a time," he said.
Josh Peter of USA TODAY Sports contributed to this article.
Follow Sean Rossman on Twitter: @SeanRossman