Well, there's an increasingly popular method which is almost guaranteed to work permanently. It's gastric bypass surgery and it shrinks the size of the stomach so dramatically that, quite simply, you can't eat much.
In 2004, more than 100,000 Americans had the operation. Among them is soprano Deborah Voigt, one of the world's great singers and a diva revered in opera houses from La Scala to the Met.
At the same time, she was an all-American girl who grappled for years with an all-American habit of eating too many heavy meals — and a weight problem that, like her talent, was off the scale.
Correspondent Bob Simon reports.
For most of Deborah Voigt's career, she embodied — literally — the old saying that in opera, great voices often come in large packages.
"I don't expect you to answer but I'll ask anyway. How much did you weigh?" Simon asked.
"Well, you're right, I'm not going to answer that. My pat answer is you don't ask a woman how much she weighs or how old she is. I'll tell you that when I started I was a 28, 30 dress size, which is quite large," says Voigt.
She has lost at least 135 pounds and she is down to a size 14. And though she'll never be skinny, the transformation is stunning. Wherever she goes these days, Voigt's fans all say the same thing: that she looks gorgeous.
Voigt is used to getting compliments but, until recently, gorgeous was not among them. And there's still a part of her that just doesn't believe it.
"I look in the mirror and I still see a large person," says Voigt. "I had some publicity pictures taken recently and my first reaction was 'My goodness. Look at that woman. She's so beautiful. She looks fabulous.' And then when I look at it closer and I think, 'Oh, but you know, I'm still a little too big here and I'm still this here.' "
Voigt agrees the mind can be slower than the body. Her body has changed, but she says, "the mind is still playing catch-up. No question."
It was 15 years ago that Voigt's career took off with a stunning Boston performance of Richard Strauss's opera "Ariadne auf Naxos." John Rockwell, an influential music critic, happened to drop by.
"(Rockwell) wrote a review in the New York Times that was something that my mom couldn't have written, it was so magnificent," Voigt says.
Ariadne would become her signature role. Recently, she was scheduled to sing it at London's Royal Opera House in Covent Garden until fate — and weight — intervened.
"I got a call saying that it had been determined by Covent Garden that I was not appropriate because of the costume that Ariadne was meant to wear in this production. And that they were canceling my contract," Voigt says.
Asked what the costume was, Voigt says she hasn't seen it but says, "It has become known as the little black dress."