The cost of attending an adult weight-loss retreat ranges from about ,000 to ,000 per week. Contestants on The Biggest Loser experience dramatic weight loss, but the show has come under fire because its results are sometimes temporary.

In 2009, for instance, season-three winner Erik Chopin -- who lost 214 pounds on the show -- told Oprah Winfrey that he had gained most of the weight back.

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Studies of the Pritikin Longevity Center & Spa, in Aventura, Florida -- the most researched program of its kind -- have found that guests lose between 4 percent and 5 percent of their body weight.

(Other measures of health, such as their cholesterol levels and blood pressure, also tend to improve measurably.) Skinny up your weekend As for the permanence of the weight loss, a study conducted by researchers from the University of South Carolina found that one year after their stay, just 22 percent of Hilton Head Health guests weighed 10 percent less than they did when they entered the retreat.

At 5 feet 10 inches, the software-company executive from Newport, California, then 40, was 280 pounds.

Her weight had always fluctuated, but she decided that she wanted to slim down once and for all.

For a more relaxed approach, there's Green Mountain, a "non-diet" weight-loss program in Vermont exclusively for women. While the theme and day-to-day schedule varies at each retreat, most programs are structured around exercise, healthy meals, and lifestyle education.

At the Hilton Head Health Institute, Ackerman ate three restricted-calorie meals a day (followed by 20-minute walks), and had exercise sessions, nutrition lectures, cooking classes, and behavior modification seminars. Here's how to keep it off Features such as these don't come cheap.

Our weight loss program understands the daily struggle with weight loss and how it affects the entire family. We’ll have lots of fun and you’ll get the necessary support for lasting change.

( -- Five years ago, Juli Ackerman never thought she'd be able to buy an off-the-rack wedding dress.

These weight-loss retreats market their services in a variety of ways.