It wasn't that difficult. I wasn't as much full, as I was just tired of chewing. That's a lot of beef to eat, and your jaw gets tired after a while.
It took me 45 minutes to eat the meal, which includes the steak, toast, baked potato, and salad. You are required to finish it in 1 hour and 15 minutes. (in order to get the Beefeater's medallion)