From Big Texan Steak Ranch:

 In the early `60s when Bob Lee first opened the Big Texan Steak Ranch the cowboys still came into town at the end of the week.  One night a lanky cowboy came through the front door of the restaurant declaring he was so hungry he could "eat the whole darned cow."

Bob, always ready to have some fun, gave him a big grin and started cooking steaks.  When the cowboy finally yelled, "calf rope," he had consumed 4 ½ pounds of meat.  Bob declared from that day forward, the meal would be free to anyone who could eat it all in 1 hour.  

[...]

About 8,000 have succeeded in completing the feat and joining the ranks of Big Texan champions.  They come from all walks of life.  Winners have included an 11-year-old boy and a 69-year-old grandmother. Former Cincinnati Reds Pitcher Frank Pastore did it in a record time of 9 ½ minutes.  The unofficial record for the fastest time belongs to a Bengal Tiger.  His meal was limited to the steak only and he dined in the front of the building.  The technique was the simplest we've ever seen: sniff, lick, gulp!  It took him less than 90 seconds.

I can't even begin to imagine how sick you would feel after downing four and a half pounds of steak in under ten minutes. Wow.