These sort of things aren't hugely popular in the UK. However, it is growing in popularity with the rise of shows like Man Vs Food and also YT channels like Epic Meal Time.

That being said, most of the challenges you get in the UK are way out of proportion to that which the average Brit can manage due to the fact that our portion size on average is a lot smaller than the USA. I remember Paul linking to one in particular about steak. However, the steak was so huge that it didn't even look cooked properly. It looked burnt on the outside, raw in the middle and was described as "medium rare" by the papers. It wasn't medium, it was just cooked badly.

Ultimately, some of them look amazing, especially some of the crazier stuff that actually could work done on shows like Epic Meal Time. However, I barely manage to eat a plate and a half in your average all you can eat China Town buffet. I doubt I'd ever be able to do one of these.