The pizzas competition 2

I underlined a couple of things that need fixing or could be improved:

The participant who ate the most number of pizzas would be the winner. When the competition began, all of them gobbled pizzas up as fast as possible and as much as they could. They looked nervous and felt hot eating the pizzas. Some of them drank water while eating pizzas as well. The audience cheered and gave them support.

I wondered if this was homework, hence my suggestion that you should try first!

The participant who ate the most pizzas would be the winner. When the competition began, all of them gobbled pizzas up [This is OK, but I personally prefer "gobbled up pizzas". The theory is that you shouldn't split a compound verb, such as "gobble up", unless the sentence structure really requires you to do so] as fast as possible they could they possibly could. They looked nervous and felt hot eating the pizzas. Some of them drank water while eating pizzas [this is not wrong, but by now we get the idea that it's pizzas they're eating, and the repetition tends to get a little tiresome]. The audience cheered and gave them support.