O's 90-Day Fitness Challenge

The idea is simple. Four women sign on for three months of fitness reeducation camp. None have serious weight problems, but all strive to slim down and tighten up. They share checkered dieting pasts—from Weight Watchers to Cabbage Soup to nothing at all. Not one has found a program that lasts.

At this camp, there's only one counselor: fitness expert Jim "Toss the Treadmill and Step Up the Strength Training" Karas. Jim's last appearance in O was in April 2002, in a feature on his training regimen for client Diane Sawyer. Except for monthly update sessions at O's New York offices, this camp is set up as a distance-learning situation. Will it work? Could it work for you? Here's a chronicle of the project to show where it did—and didn't—work and why.

Session 1: January 30

The participants meet Jim for a two-hour pep talk. He gives out copies of his book, The Business Plan for the Body, and at-home exercise equipment, including an inflatable exercise ball and elastic bands. Jim's website (JimKaras.com) will be a free resource: The women can print out menu plans, blank food diaries, and exercise logs.

Jim briefs them on diet and exercise, after asking about their routines. Gayle King, 47, O's editor at large, hasn't been on an official diet in five years, though she does get on her treadmill five or six days a week. She wants results, but she knows she's got problems: Gayle's never met a buffet she doesn't love, for example, and a good focaccia is as satisfying to her as...well, she's got problems.

Taryn Esposito, 25, tried working with a nutritionist, but just as she started, along came the winter holidays and all the associated temptations. Taryn stopped going. She likes eating out, she likes wine and cocktails, but she also likes to exercise, averaging 45 minutes on various cardio machines six times per week.

Cindy Paragallo, 34, has been going to a nutritionist for four months; she's lost only three pounds. She works out four times a week, alternating between the elliptical machine, Bikram yoga, and kickboxing.

Pat McLaughlin, 51, comes in from her job in Connecticut and arrives after the meeting is well under way. She exercised religiously in her thirties and forties, but her job, home life, and volunteer work leave her no time for herself, much less for working out.

Jim calculates everyone's current caloric intake, then prescribes a lower number. "If you're carrying too much body weight," he explains, "you've just taken in more energy than you've used."

While Jim leaves it up to the women to choose what to eat, he has what could be considered strong opinions on the subject. The gospel according to Jim consists of foods that he either loves or finds brutal. Loves: berries, pineapples, frozen fruits and veggies, Dijon mustard, pickle relish, salsa on baked potatoes, salsa on baby carrots, salsa (as dressing) on salads. Also Dannon Light 'n Fit yogurt. Brutal: creamed spinach, salad dressing, nuts, peanut butter, salted microwave popcorn, and buttery mashed potatoes ("Off the charts!").

What to eat shifts into how much. Even if the food choices are healthy ones, portion sizes can blow a diet. "It's shocking when you see the real caloric value for a portion size. And being unprepared for a situation can lead to unhealthy choices."

"I'm going to ask you to plan every day," he says. "Make appointments with yourself to exercise. Look at your meals for the coming week. See what social or business things you've got. And remember: Water is the elixir of the gods."

Jim likes his clients to stay hydrated—water, he believes, keeps the body's systems functioning at peak performance.

"Not juice?" Gayle asks. "Like Cran-Apple, Cran-Grape?"

"Lots of calories," Jim pronounces. Gayle pleads her case: "After I work out and I'm so thirsty, I need something sweet."

"Okay, why aren't you drinking water? Are you drinking lots of water?"

"No. I do a whole liter of that CranGrape. Two liters, easy."

Jim is clearly impressed. "Can you really drink two liters?"

"Easy."

"Do you know, Gayle, if you cut that out, you could really lose weight." Gayle falls silent and stares into the middle distance, struggling to imagine a world without juice.

Next, Jim turns to exercise. Each workout should take an hour: 15 minutes of cardio and 45 of strength-training exercises.

"Do you train every day with the weights?" Pat asks.

"That's not necessary," Jim answers. "Four times a week would be wonderful. Three is fine; two if you work really hard."

Jim demonstrates 15 basic exercises, pulled straight from his book—from biceps curls to squats and lunges. As soon as they can complete 15 reps of any exercise, Jim says, they should increase their weights, use tighter bands, or slow down the movement. "Keep challenging the muscle."

He finishes with abdominals on the inflatable ball, and a recap of his own advice: "Send me your food diaries, increase your caloric awareness, eat lots of fruits and vegetables, drink lots of water."

Next: "I didn't just fall off the wagon, I fell into the river and was paddling without a lifeboat!"