Thinner

Another Richard Bachman - one of my favorites actually.  This is a twisted little tale about a fat lawyer who runs over a gypsy who was passing through town (she was jaywalking), he does not get punished for it by the legal system (connections, it pays to have them) so the gypsy's father puts a curse on him.  To do this he touches his cheek and says "Thinner". The lawyer stars fairly quickly to lose weight regardless of what or how much he eats, which at first is not so bad, but when a month goes by and he has lost 70 pounds, that is a extremely worrisome.  At this point he knows that he as been cursed, but his doctor and wife do not believe it and instead look for some other explanation.  Billy (our hero/lawyer) decides to track down the wandering band of gypsy's and confront this man about the curse asking that it be lifted.

When he finally finds them, he is very emaciated, his wife and doctor have had him committed in absentia, and time is ticking.  The gypsy refuses to remove the curse, so Billy curses him with the "white man from town" curse and calls in a friend of his who is a made man.  This guy starts out by killing their fighting dogs, then shooting up the camp, and finally by threatening to poor acid on the beautiful granddaughters face. The old gypsy decides enough is enough and calls a truce, saying he will remove the curse.  However, it is not that easy.  He puts the curse in a strawberry pie and tells Billy that whoever eats the pie will get his curse. So Billy decides to feed it to his wife so he can live a nice happy life away from it all with his daughter.

But, things don't always turn out as planned and in the end he discovers that Karma is bitch.