A woman was terribly overweight, so her doctor put her on a diet.
"I want you to eat regularly for 2 days, then skip a day, and
repeat this procedure for 2 weeks. The next time I see you, you'll
have lost at least 5 pounds."
When the woman returned, she shocked the doctor by losing nearly
20 pounds.
"Why, that's amazing!" the doctor said, "Did you follow my
instructions?" 
The woman nodded. "I'll tell you though, I thought I was going to
drop dead that third day."
"From hunger, you mean?"
"No, from skipping."