The 13 Fittest Cruise Ships

Cruises are traditionally a dieter's worst nightmare, almost on a par with French fries, glazed donuts and supersized sodas. According to a survey of more than 1,200 British cruisers, for instance, 52 percent said they'd gained up to 14 pounds during a two-week holiday. Even worse? About six percent reported putting on up to 18 pounds. But going on a cruise doesn't have to mean being cooped up, doing canned excursions, and letting your waistline bulge while you eat coconut shrimp by the pool.

Click to see which cruise lines top our list of 13 fit ships.

Instead, it can mean early morning Tai Chi classes on deck, getting a personal training session in a state-of-the-art fitness center with sweeping views, or putting in an early evening jog in the fresh ocean air. As the public becomes more and more health conscious, cruise lines are offering better options—by way of expanded gyms, fitness classes and over-the-top amenities like jogging tracks, climbing walls and artificial surf waves—to help you stay active while at sea. That way, if you're eating more food (and admit it—you will!), you can balance calories in with calories out without running up and down the stairs or doing lunges down the hallway (and attracting strange looks from fellow passengers).[slideshow:706]

Rather than aim for absolutes—and run the risk of multiple ships from the same company (Royal Caribbean, for instance, would take many slots, based on the sprawling size of its ships alone)—we picked the top ships from 13 different cruise lines, in order to serve cruisers of every stripe, from the family types who might sail with Disney to those who prefer the luxury of a Regent Seven Seas vacation. To come up with our ranking, we looked at passengers per personal trainer, size and number of fitness centers, counted every piece of fitness equipment (at least that we could get numbers for) and factored in number of fitness classes and more exciting amenities like zip lines, rock walls and sports facilities.

Ready to set sail on a fitness-friendly cruise? Here are 13 ships with calorie-crunching fitness offerings onboard to keep your waistline intact.

Click here to see 13 cruise ships that'll keep you fit.