Joey Chestnut ate 71 hot dogs in 10 minutes on July 4.<br />He narrowly missing his previous record of 74.<br />Scientists have studied the bodies of competitive eaters like Chestnut.<br />They found that their stomachs don't contract normally.<br />Business Insider says competitive eaters can relax their stomachs to hold more food.<br />The sport can take a toll on normal kidney, liver, and heart functioning. <br />
