in the olympics i noticed when like the chinese or some people win a gold they try and bite it?

When metals,especially gold, was used more often as currency, people would bite it to see if it was 100% gold. If you can bind it with your teeth, then it most likely was not all gold or 100% pure. As for the olympians, they just spent four years training their heart out. I think a little silly moment is called for after so much tension.

It isn't just the Chinese, people from all countries pull this joke. They are pretending to test the metal to make sure it's real gold (which it isn't, it's just gold-plated), instead of a weak cheap metal like tin painted gold, or a chocolate coin in a gold foil wrapper. Biting the coin or medal is a traditional way to test its strength.

They don't actually think it's fake, they are just making a joke. Don't insult people or mock them until you understand their motives, or you'll be the one looking foolish.

They want to make sure it is real and not chocolate with gold plating on it lol.

They just pretend it's just chocolate just for fun.

The Chinese kids are really hungry. You saw how skinny those 8 year old female gymnasts are, right?