By 7:15 the first morning at sea, the Ship Shape Fitness Center on Voyager of the Seas was alive with passengers. They had all 20 treadmills going, the 13 elliptical machines in motion and most of the bikes spinning.

By 8 a.m., the Sunrise Stretch class was warming up. Dozens of people were using free weights, weight machines, stationary bikes and stair steppers, and my water aerobics class was ready to take the plunge.

This was not the gorge-and-doze kind of cruise -- unless that's what you wanted it to be. The agenda, part of Royal Caribbean's new Vitality program, included more fitness and spa offerings, wholesome culinary options and endless activities on board and in ports of call.

"I don't want to float and bloat," said Giselle Brabb, 72, who walked three miles (15 laps) around the open-air track on deck every morning during the seven-day cruise out of Galveston, Texas.

"That and a little ab work and free weights are what I always do for exercise on cruises. At home, I go to the gym every other day, but I have to work harder here because I eat more."

At 142,000 tons and built for 3,114 guests, Voyager of the Seas was launched in 1999 with the first full-size skating rink and rock-climbing wall available at sea.

The sports deck includes a serpentine in-line skating course with padded walls; a basketball and volleyball court; pingpong tables; miniature golf; a virtual driving range; and a golf hitting cage. On the uppermost foredeck, a spa offers acupuncture and teeth whitening as well as mud baths and massages.

Just below the spa is the fitness center, where you get a panoramic view of the ocean from the treadmills in front of floor-to-ceiling windows.

None of the big ships caters exclusively to passengers eager to exercise and eat healthfully, but the Vitality program encourages them.

"We are more into helping people change their lifestyles than ever before: the way they eat and exercise and think," said Vivian Belbeck, the Voyager's spa and salon manager. "You are more able to reap the benefits of a spa when you have time to relax. It can be life-changing."

Some passengers, including my 88-year-old mother and a group of her friends, booked through Fun & Fitness Travel Club. The organization has no dues or fees, no meetings and about 3,500 members who travel with their water exercise classes and certified instructors from home.

While I was on board, seminars were conducted on topics including "Secrets to a Flatter Stomach," "Detox for Health and Weight Loss," "Burn Fat Faster," "How to Increase Your Metabolism" and "Eat More to Weigh Less." There were poolside swimsuit contests for things like "Best Triceps" for women and "Best Belly Flops" for men.

The cruise line partners with New Balance to bolster the Vitality program with a virtual personal trainer to help guests create customized fitness regimens as well as post-vacation exercise plans.

As for food, you have every option, whether you want to taste everything or follow a special diet based on allergies, weight goals or cholesterol control.

In the elegant main dining room, as well as the casual Windjammer Cafe, low-fat and vegetarian entrees are always available along with sugar-free, fat-free and vegan desserts. I felt a little foolish one night at dinner bragging about how rich and delicious my full-fat cheesecake was when I tasted my daughter's fat-free version and realized they tasted exactly alike.

My best advice is to take a complete walk around the buffet the first day, before you ever start filling your plate, so you see all the choices -- egg white omelets, turkey sausage, fat-free yogurt, an oatmeal bar with walnuts, raisins and dried apricots, three kinds of pizza (including veggie), sushi, fresh fruit, huge salad bars that stayed fresh and tasty all day, low-fat and fat-free milk and a make-your-own-sandwich bar.

"This is really something that's catching on," said Randi Butcher, a 43-year-old health-conscious cruiser from Short Hills, N.J., whom we found in the fitness center the last evening of our cruise. She had worked out with weight machines six days and run 16 to 18 times around the deck two of the days we were at sea.

"And I took a stretching class," she said. "I always work out at home, and I've been eating too much on the cruise so I can't stop now."