"I've eaten better" or "I've ate better"

There's an argument about which is correct of these two sentences.

"I've eaten better" and "I've ate better"

Now the whole argument started when someone was talking about how great the food she ate last night was, the responder replied by saying "I've ate better food than that", it, however, broke into an argument on which sentence is correct or the two statements.

Can anyone help settle this?