I think we can all safely separate food challenges into three categories, with hybrids of both:

Spicy: Can you eat all the hot food/drink here?

Gorging: Can you eat all the food/drink here?

Time: Can you eat all the food/drink here in a certain period of time?

After watching Man vs. Food enough, he tends to suck at the second too, and average at the first.

I think spicy's are the easiest.