Dieting Brunette

A brunette is overweight, so her doctor puts her on a diet. "I want you to eat regularly for two days, then skip a day, and repeat this procedure for two weeks. The next time I see you, you'll have lost at least five pounds."
When the brunette returns, she's lost nearly 20 pounds.
"Why, that's amazing!" the doctor says. "Did you follow my instructions?"
The brunette nods. "I'll tell you, though, I thought I was going to drop dead that third day."
"From hunger, you mean?" asked the doctor.
"No, from all that skipping."