If you want to see the emotional and physical toll that diets, deprivation and being pushed to physical extremes can take -- and we don't blame you if you don't -- tune in to "The Biggest Loser," the newest reality television show.

In tonight's episode, a dozen desperate obese men and women begin a personal weight-loss odyssey on NBC. "I don't take my shirt off for my family, I can't believe that I'm doing this on national television," one participant laments as the group lines up for the first of their regular public weigh-ins on a humongous scale.

Over nine shows, viewers will watch as two teams of three men and three women (weighing a little more than 1,500 pounds per team at the beginning) live together on a ranch in Malibu. Rather than consider what weight loss plan might work best for every individual, the script calls for each team to be assigned to one of two diets. Both limit portions. One regimen is based on the glycemic index -- which takes into account how much a food raises blood sugar levels. The other focuses on eating six small meals per day.

Two personal trainers with nearly opposite philosophies put the would-be losers through physical paces so grueling (at least during the first show) that it reduces some to tears. One contestant vomits.

Oh, yes, and hovering in the background are glass-fronted refrigerators, labeled with each contestant's name and filled with their favorite high-calorie foods. The team that loses less weight each week must vote a member off the show. The last remaining contestant will win a $250,000 prize.

And what do leading weight-loss experts think about this exercise?

"Very humiliating," said Albert Stunkard, professor of psychiatry at the University of Pennsylvania and a pioneer in the study of obesity.

"Both cruel and counterproductive," said Xavier Pi-Sunyer, director of the New York Obesity Research Center, St. Luke-Roosevelt Hospital, chairman of the National Institutes of Health Obesity Guidelines panel and a member of the 2005 Dietary Guidelines Committee.

"Competition may be a benefit to some people, but it's not a benefit when it damages self-esteem," said Thomas A. Wadden, director of the Weight and Eating Disorders Clinic at the University of Pennsylvania. "If you slip up, you can feel doubly bad because you're letting down the team."

Having said all that, a few things can be learned from this show:

Don't try this at home. The artificial lose-as-much-as-possible-in-a-week philosophy violates a major tenet of healthy habit change, the premise upon which the Lean Plate Club is built. The way to achieve long-term weight loss is to change habits for good, not to sprint to see how much weight you can lose under pressure.

As David Katz, director of the Yale Prevention Research Center, likes to say: "You can lose weight with chemotherapy and crack cocaine, but would you want to?"

Also, some of the contestants lost 10 or more pounds in a week -- far more than the half-pound to two pounds per week considered a safe rate, experts say. (And don't be fooled: Rapid and large drops in weight are due mostly to diuresis -- water loss.)

Go ahead, compete -- but within limits. Jump-starting your efforts with a small dose of good-natured competition may provide some extra motivation toward a healthier weight, according to Stunkard. Just be sure there are limits -- say, a pound per week per person -- so that no one gets too carried away and tries crash diets or fasting.

Reality check: Competition gives no lasting edge in long-term weight-loss success. "It's good for initial weight loss, but when people are pushed for longer [periods], they don't maintain it," Stunkard said. "And if they don't lose [enough] weight, it adds to their shame and failure," Wadden said. "It triggers those feelings of thinking 'I have no willpower. I'm not successful. Look how I've let people down again.' ''

Get a physical exam. Participants in "The Biggest Loser" not only underwent physical exams prior to the show but also were monitored regularly during the tapings by two physicians. Experts say physical exams are particularly important if you've either got a lot of weight to lose or haven't had a recent checkup. Gallstones and irregular heartbeats are two potential weight-loss complications for those who are obese or who try to lose weight too rapidly.

An electrocardiogram, which monitors heartbeats, is one of the essential tests used by many clinic-based weight loss programs. Obese people who lose weight rapidly "need an EKG once a week," Pi-Sunyer said. Those who lose about a pound per week need an EKG every four to six weeks to monitor heart rate and be sure that no electrical abnormalities have developed, he said. That's something that most commercial weight-loss programs and diet books fail to recommend.

Find support. Stunkard has organized weight-loss contests pitting individuals or teams against each other at work sites. Both men and women lost more weight and stuck with their weight-loss efforts longer when they were part of a team, Stunkard found. (Dropout rates were just 1 percent during 12-week work site contests.) So if you can't get a team going at your office or within your extended family, find a buddy to help support your efforts. In a recent Lean Plate Club Web chat, a member from Michigan noted that she uses the Web to stay in contact with her exercise buddy in another state. The President's Council on Physical Fitness and Sports (www.fitness.gov) offers a free tool to enable you to set up your own password-protected fitness group -- and to pursue a presidential medal if you choose.

Take charge. Participants in the show were told what diets to use and when and how to exercise. Research suggests that any diet will help you lose weight in the short run. If you want to sustain that loss, you have to find the healthy foods and physical activity that you like best. If you don't, the habit changes won't last.

Plan to avoid temptation. To reflect the many choices in real life, "The Biggest Loser" puts participants' favorite high-calorie foods within reach, beginning with breakfast tables laden with platters of bacon, sausage and pancakes as well as fruit and whole grain cereals. "It's very important for the viewer not to say, 'You put me on a ranch for 70 days, get me a trainer and I will lose weight too,' " said Dave Broome, an executive producer of the show. "So we made a show about choices." But most research suggests that it's important to surround yourself with good choices and to step away from the foods that are likely to trigger overeating.

Ratchet up physical activity slowly. Lean Plate Club members already know that it takes eating less and moving more to succeed in achieving a healthier weight. "Biggest Loser" participants get a minimum of two hours of exercise in the morning and two hours in the evening -- about four times what the National Academy of Sciences says is important for weight loss maintenance and eight times what the U.S. Surgeon General recommends on most days.Those four hours per day are unsustainable for most people in the real world. Also, going from an extremely sedentary lifestyle to that much activity overnight took a toll on participants, who complained of extremely sore muscles. So go ahead, boost physical activity to burn calories and stay in shape, but go slowly. Be sure to get instructional help as needed on weight machines and with other equipment. Aim for about 30 to 60 minutes of activity on most days, including so-called "lifestyle" exercises such as taking the stairs.

Be accountable. "The Biggest Loser" requires participants to publicly weigh themselves on a huge scale. Average Joes and Janes don't need to go that extreme, but finding a way to be accountable in some fashion is a good thing, studies suggest. Regular weigh-ins are also a key part of the Weight Watchers program. Members of the National Weight Control Registry -- a group of several thousand "successful losers" who have shed at least 30 pounds and kept it off for at least three years -- report monitoring their weight in some fashion. Various online communities, including SparkPeople and E-diets, provide it, too. So climb on the scale, check your body fat or measure your waistline -- whatever it takes to track your progress of instilling healthy habits and, if you choose, to be accountable about them to others.

Oh, one final thing: Limit your time in front of the tube. Research shows that it's linked to an increased body weight.

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Share Your Tips or ask questions about healthy nutrition and activity when Sally Squires hosts the Lean Plate Club online chat, from 1 p.m. to 2 p.m. today, on www.washingtonpost.com. Can't join live? E-mail leanplateclub@washpost.com anytime.

New To The Club? The Lean Plate Club is devoted to healthful eating and boosting activity. To learn more, and subscribe to our free e-newsletter, visit www.washingtonpost.com/leanplateclub.

A logo not to live by: New TV reality show may amuse some viewers, but not dietitians. Show host Caroline Rhea, above, presides over weight-loss shenanigans in "The Biggest Loser." Below, contestants launch their dietary misadventures in Malibu.