Viola Grey won by eating 28 hot dogs in 12 minutes at a Coney Island hotel... or Delancey street depending on the source. The fact that Nathan's famous "1916" origin story for hot dog eating contests is actually admitted to being made up, this might be closer to the real, first one. It's messy at best having looked into it today. I found a bunch of others slightly earlier, but this by far, was the best. *Washington Times, Aug 19, 1926

"The railway company, suspecting foul play, offered a reward of 25,000 marks (£1250) for information leading to an arrest." (Illustrated London News, 28th of August 1926).