Hilary Davidson was diagnosed with celiac disease eight years ago and worried at first that she couldn't maintain a gluten-free diet on the road. But the idea of staying in one place didn't suit her -- or her work as a novelist and travel writer -- so she started calling restaurants and turning to the Internet to figure out what she could eat abroad.

Davidson launched her gluten-free guidebook blog in 2006 to share her research and experiences traveling to Switzerland, Turkey, Spain and Peru, among other places. She headed to Israel last week with recommendations from her gluten-free Facebook group

Traveling with dietary restrictions, whether medical necessity or by choice, is getting easier.

Websites devoted to vegetarian and vegan eating around the world list user-recommended options. People with diet-restricting conditions like Davidson's are sharing their struggles and tips online to find safe and delicious food abroad. And tourism is developing around the concept of animals as friends, not a source of your food.

Research your options

Planning is key to the success of your trip. If you're allergic to common foods or ingredients that hide in sauces or soups, you know which foods to avoid and which foods to ask for. And if you're traveling to a foreign country, research the right words to communicate to a restaurant staff or grocery store clerk.

Dr. Oz tells vegans how to get proteins and vitamins they may miss.

"Planning frees you up to focus on the real purpose of travel, which is to experience a new culture and enjoy the people you are traveling with," says University of Washington psychologist Jonathan Bricker, who studies the psychology of travel. "You'll have a greater sense of control over your environment and a greater sense of safety when you are traveling."

Davidson always brings snacks in case she's stuck with no safe food options and website CeliacTravel.com's pre-printed cards explaining what she can eat in the language of the country she's visiting.

"When I go into a restaurant I hand over the card, and I've never had a problem getting a meal that way," says Davidson. "You also want to see if there's a local celiac association because you'll find a list of local restaurants willing and able to accommodate you. It's a lovely feeling to be taken care of that way."

Understand cultural differences

Realize that your definition of important words like "vegetarian" or "vegan" might vary by culture or by the knowledge of the waiters and kitchen staff you meet. Some people in this country and abroad think that vegetarianism includes eating fish and fish stock. Others think that vegetarian dishes are dishes that include vegetables (but may contain meat).

"You have a definition of vegetarian but that might not be the definition in the country you're visiting," says Anne Banas, a vegetarian and executive editor of Smarter Travel.

"Some vegetarian dishes (I've been served) in Germany have had fish. If you're strict, know the right phrasing. The rice may have been cooked in chicken stock and the tortillas could be made with lard."

Have a backup medical plan

Jeff Tucker, whose 9-year-old daughter was diagnosed with Type 1 diabetes three years ago, travels with his family to Costa Rica almost every year to visit his wife's family. The first year Anissa was diagnosed, they skipped the annual trip, Tucker says. They were still learning too much about how to care for their daughter on a daily basis.

"Any time she eats carbs, she needs to have her insulin because her pancreas doesn't make insulin," says Tucker, a firefighter with the North Monterey County Fire Protection District in California. "On a day to day basis, she's learning how to deal with it pretty well. She'll check her sugar and tell me what she thinks she should do."

The family travels with Anissa's primary insulin pump, a backup pump in case the first one fails and extra insulin, knowing that airport security will need extra time to examine the pumps and that local pharmacies carry a different type of insulin. Tucker's wife also has two doctors in her family in Costa Rica, whose help he hopes they never need.

You can still be a foodie

Vegetarians and vegans often turn to Happy Cow website , which launched in 1999 as a vegan and vegetarian guide to restaurants. The site has grown to include other businesses that cater to the vegan and vegetarian communities, forums and a smart phone app.

People suffering from celiac disease can eat many Indian foods that use chick-pea flour instead of wheat (avoid the naan) and Mexican food that's corn-based, Davidson says.

With multiple allergies, you might need to do more work. But it's still possible for poet and author Sandra Beasley to love food, despite multiple life-threatening allergies she's detailed in her memoir, "Don't Kill the Birthday Girl."

When she travels, she always researches a higher-end meal for pleasure and a chain restaurant where she can have a safe fallback option for a meal.

Beasley likes to enjoy local or regional cuisine, so she investigates in advance the ingredients most likely to be used, whether it's a spice rub or sauce. In certain parts of the United States, she can eat barbeque with a tomato- or vinegar-based sauce. She's allergic to mustard, so she can't eat barbeque with a mustard-based sauce.

Beasley will pack nonrefrigerated foods that she knows are safe as a backup if she can't find safe food to purchase. On road trips, she'll often take a cooler to carry microwaveable meals and refrigerated food and stay at hotels or motels where she knows all the rooms have refrigerators.

While some people with allergies only experience mild discomfort, Beasley isn't so lucky. She was often rushed to the hospital as a child because her allergies can kill her.

Be polite, but trust your gut

With requirements that include an absolute prohibition on dairy touching any of her food, Beasley knows she might be making life more complicated for the kitchen staff.

She's very polite as she interviews her waiter. "Manners are really important when you're traveling," says Beasley. "You're working with someone to create a safe and enjoyable experience. I usually tell the waiter, 'Don't be scared. This is going to work out just fine.' They're part of your vacation but you're part of their workday."

That said, she'll leave if she senses the water is uncomfortable with her list of allergies. "If someone looks at you and says, 'We fry mozzarella sticks in same place we deep-fry French fries,' unfortunately you have to walk next door," she says. "Once you ask the questions, trust your gut."

If the degree of knowledge doesn't come down the chain of command of the restaurant to the waiter who's talking to her, she can't trust the food will be safe.

Find like-minded tourism

Vegans have more like-minded travel options beyond just where they eat. Farm Sanctuary , one of the top tourism attractions in Watkins Glen, New York, provides tours and overnight rooms at its sanctuary for rescued farm animals.

"Many people who visit come because they want to see animals, think it's a petting zoo and are introduced to the idea that we don't have to eat animals, " says Farm Sanctuary president Gene Baur, who co-founded the sanctuary in 1986. "Other folks are curious and are interested in what their vegan friends (who support the sanctuary) are saying."

There are also vegan bed and breakfasts popping up near the sanctuary and elsewhere whose owners serve only vegan food and don't use any animal products (like soaps) at their establishments.

The Red Robin Song Guest House , on the New York state side of the Berkshires, serves a vegan breakfast that can fool the doubters, says co-owner Lisa Robinson-Redd, who started the business a year ago with her husband, Jeff.

"We saw the guesthouse as an opportunity to educate people about the advantages of a vegan diet," says Robinson-Redd.