Fit Club Trainer: I'll Rip Screech's Head Off

Harvey Walden has worked with a lot of wannabeens on "Celebrity Fit Club" -- but there's one guy in particular he says belongs on Celebrity "Piece of S**t" Club.

The fatty in question: "Dustin Screech Dumb Ass Diamond," who Harvey despises soooo much, he threatened to "rip his head off and fill his throat with low fat yogurt."

Someone get him some Yoplait!