This one is based on a novel Stephen King wrote under his pseudonym, Richard Bachmann. I think I saw this piece of crap in the theater.
The premise is that a rich, fat guy runs over a gypsy while getting a blow J. When justice is not served in court, the gypsy's son curses the man to become thinner. Most of the movie is spent with the fat lawyer quickly losing weight and trying to figure out how to stop the curse. Mostly, he tries using mob ties to send hit men after the gypsy. There are retaliation murders and things just get silly by the end with a poisoned strawberry pie.
As much as I have often wished for a more gentle version of this curse, the movie does a pretty bad job of demonstrating the effects. The fat suit on Robert John Burke is not convincing. The murders and gunplay that figure into the latter half of the movie are ridiculous. Even for bad Stephen King adaptations, I would say this is one of the worst. While the ending is suitably horrific, everything leading up to it is kind of silly.
If you can't tell I would not recommend this.