Remember when beach vacations were for eating too much, drinking too much, partying until dawn and lying in the hot sun doing nothing?

Many people today are using their vacation time to do just the opposite. With precious days away from a hectic work schedule to attend to health goals, the vacation is emerging as an opportune time to focus on fitness.

Special (ENLARGE)

If you're going to have a cocktail , 'The mimosa is probably the best bet,' nutritionist Donna Shields says.

(ENLARGE)

A vacation is a good time to put away car keys and ride a bike.

RELATED LINK: • More Health stories

Registered dietitian Donna Shields has noticed this emerging health trend in her conversations with locals and visitors in Key West, Fla., where she is a self-professed "southernmost nutritionist" and "diet coach to the beach bums."

Shields, a slim and trim 50-something brunette, was attracted to the casual beach life in the Florida Keys. But as a certified personal trainer and former nutrition instructor for the Culinary Institute of America in Hyde Park, N.Y., she is serious about promoting diet and fitness.

Author of the cookbook "Caribbean Light" (Broadway, $25.95), she's also well-qualified to help clients slim down a piña colada or add a tropical flavor to grilled fish. So today, I go to the Keys to learn about the keys to a healthy vacation from Shields (www.donnashields.com).

Carolyn: Vacations used to mean eating everything in sight and dropping out of everything including our fitness goals, but today it seems that busy folks want to use their extra time on vacation to take care of themselves.

Donna: Leave the car keys in the hotel room and start walking everywhere. This is so simple in a small town like Key West, where it's flat and accessible. But even if you're in a more remote resort location and need to drive places, you can still make it work. Have the taxi leave and pick you up at the opposite end of town and walk to your destination, especially if it's for dinner. If you want to lounge by the pool, promise yourself that the next day you'll do something more active, like kayak.

Even fishing can be strenuous if you're going after big tarpon or sailfish. Check out where the locals go for exercise classes. Find out from the concierge where the neighborhood yoga or dance studio is. It's a good way to meet non-tourists and get the skinny on the town. And don't forget about yoga classes on the beach. Bet you can't do that at home.

Carolyn: In the Keys it seems everyone rides a bike instead of renting a car. What can bike riding do for you?

Donna: Biking in Key West is what I would call functional exercise. We don't really think of it as exercise but simply a way to get from one place to another.

It's practical, quick, very green and there's no hassle or cost of parking. It's great for the quadriceps muscles, which don't get much use if you're used to sitting at a desk all week. Though we ride cruisers and not racing bikes, the town is completely flat so it's easy even if you haven't been on a two-wheeler for 20 years.

Carolyn: Tropical vacations seem to bring to mind fresh fish and fresh fruit ... but, of course there's plenty of french fries and beer. What kinds of foods do you recommend during vacation?

Donna: Order the local seafood if you are near the water. In our case, it's often Key West pinks [shrimp], dolphin [also called mahi-mahi], grouper and our namesake conch. Order it blackened, grilled, pan sautéed; anything but fried. Mango and other tropical fruit salsas can be a healthy accompaniment to an entree or as a sandwich topping. They offer lots of fresh flavor, few calories and a nutritious choice. And when you do want that over-the-top dish, share it with your traveling companion.

Carolyn: OK ... I'm at the pool at the historic Casa Marina Resort and the waiter comes by with a tray of cocktails. Which one should I get? Mimosa, piña colada, mojito or the strawberry daiquiri?

Donna: The mimosa is probably the best bet. The orange juice at least provides some vitamin C. Frozen blended drinks such as Key West's famous margaritas are usually loaded with sugar, made from presweetened mixes. Piña coladas are a double whammy because of the fat in the cream of coconut.

Carolyn: What are the health benefits of walking on the beach and just relaxing?

Donna: Feeling healthy can take different forms for different people. While having fun on vacation is important, doing something nice for yourself can also make you feel better. If you never get a chance to read a book, then lying in a hammock, swinging under a palm tree, with a good read might just be the thing you need to do. It's the little, unexpected, moments that make a vacation healthy for body, mind and spirit.