But in restaurant dining -- and 50 percent of American meals are now consumed outside the home -- making the right choice can be daunting.

And despite the trend of noting farms on the menus at upscale restaurants, at most meals diners have few clues about where their food comes from.

Several ambitious organizations are aiming at taking the guesswork out of eating out.

Study after study shows that Americans want to eat more healthful and sustainable food.

Each has its own certification program that aims to make it easier for diners to find places that have undertaken the complex process of serving healthful food from farms committed to animal welfare and sustainable growing practices.

The first, REAL Certified, is a homegrown initiative.

REAL, which stands for Responsible Epicurean and Agricultural Leadership,

REAL Certified doles out points to restaurants for offering a certain percentage of dishes containing vegetables, whole grains, local and organic ingredients and alternatives to sugary sodas, among other things.

"We are trying to figure out which restaurants are doing the right things and give them credit" says Lawrence Williams, founder of the United States Healthful Food Council.

SPE Certified has a similar model.

Certified dishes, except for desserts, may use no butter or cream.

The three letters stand for Sanitas Per Escam, Latin for "health through food".

The program also rates restaurants on their sourcing and environmental impact.

Ingredients cannot be fried or grilled.

But founder Emmanuel Verstraeten says SPE is less about what chefs can't use than about what they can.

His culinary team works with restaurants with the goal of offering delicious and satisfying dishes without resorting to the easy tricks that make restaurant food so unhealthful.