For Leah Shannon, it was a visit to Manhattan's Pure Food and Wine restaurant three years ago that did it.

She'd heard about the raw foods diet a few years before and thought it was just another fad. But eating at the restaurant, founded in 2004 in the Gramercy district by Matthew Kenney and Sarma Melngailis, was a revelation.

"Oh my goodness, I had these noodles, this pasta that was made with pressed, dried nuts. And then we had sushi that was made with nuts that looked like rice," she said. "It was amazing. I just couldn't believe that everything was raw."

Not long after, when she was pregnant with her first child, she began to experiment with raw food recipes. Now she has a small repertoire of favorites that she shared with a group of 15 on a recent blue-sky Saturday afternoon at Mildreds' Daughters Urban Farm in Stanton Heights, including zucchini pasta with marinara sauce; cone-shaped temaki sushi; Mediterranean chard with pine nuts, black olives and red bell peppers; marinated green beans; and brownies.

In my notebook I was ready to record the flavors, the textures, the aromas, every nibble and nuance of the experience. But the truth is, I was lost in food so uncommonly good I forgot to reach for pen and paper until my plate was almost empty.

And that's why Ms. Shannon, a native of the Philippines, now makes raw-food dinners once or twice a week, incorporating them into her family's regular diet of traditional dishes with an Asian twist, such as chicken salad dressed with sesame oil instead of mayonnaise.

"It was all on taste," she said. "I wasn't even considering the health benefits of it. It was delicious."

And the health benefits, raw foodists say, are substantial, and one of the reasons the diet is growing in popularity here and in Europe. At least 28 states have raw-food restaurants and there are more than 6,000 raw foodists in meetup groups in 69 cities, including Pittsburgh (rawfood.meetup.com/196/). The annual Raw Spirit Festival in Sedona, Ariz., now in its third year, celebrates healthy living with three days of music, lectures and raw food demonstrations each October.

Raw foodists believe heating foods beyond certain temperatures kills beneficial enzymes that aid digestion, causing the body to work harder to manufacture more of them, thus depleting the body's resources and making it more susceptible to disease and aging.

But there isn't universal agreement on that point, and Leslie Bonci, director of nutrition at UPMC's Center for Sports Medicine, is one of the dissenters.

"I am not convinced that by cooking food you destroy all of the enzymes," she said. "I don't think there's been enough science."

Plus, she and Ms. Shannon say, studies have shown that the application of heat does render some nutrients, such as lycopene, more easily absorbed and utilized by the body.

"To me, the positive about this is it definitely gets people eating more plant-life food than they ever would have before," Ms. Bonci said. "The vital nutrient intake and the fiber and the vitamins and minerals all go up dramatically."

And as Ms. Melngailis points out in her cookbook, eating raw foods can just make you feel better.

"Heavy and processed foods make you feel heavy and sluggish," she writes in the introduction to "Raw Food/Real World," which she co-wrote with Mr. Kenney. "Light, clean, natural, and alive foods make you feel light, clear and more alive."

Rene Oswald, a nurse who lives in Florida's Palm Beach Gardens, believes her raw food diet cured her mastocytosis, a cell disorder that left her with hives and affected her stomach and intestines. But at first she didn't stick with it, reverting to her vegan diet.

"As soon as I started eating cooked food at all, I got sick again," she told the Palm Beach Post. She's been on a raw diet ever since.

People who maintain a raw or "living" food diet range from 75 to 100 percent raw. While most do not eat animal products, fresh seafood and dried meats can be part of a raw foods diet, too.

But if you're thinking the raw foods diet is as quick 'n' easy as opening a bag of salad greens, forget it. Preparing raw foods can be every bit as time-consuming as cooking, what with all the vegetable chopping and marinating, nut soaking and seed sprouting.

Ms. Shannon developed and adapted the recipes in her rotation because they are easy for a busy, working mother to prepare. And they have another advantage: no standing over the stove on a hot summer day.

Although some raw food recipes require a dehydrator, juicer or mandoline, Ms. Shannon gets along nicely with only a food processor and blender -- plus one magical gadget essential for making thin strands of zucchini pasta: the spiral slicer. She recommends the Saladacco, which retails for about $30.

But all you need is a vegetable peeler to make the wider zucchini fettucini -- just shave off the zuke "noodles" and warm them in a colander over water that has come to a boil and has just been removed from the heat.

Ms. Shannon serves zucchini pasta with a marinara made from fresh and sun-dried tomatoes, red bell pepper, extra virgin olive oil, fresh basil and oregano, all combined in a food processor.

"The sun-dried tomatoes give it a more cooked taste," she said.

"Using the spiral slicer was very easy and fun," said Marlene Katz of Upper St. Clair a few days after the class. She left it so inspired that she stopped in the Strip District on the way home and bought one of the slicers.

Topped with the marinara, the spaghetti-like zucchini tastes surprisingly like the real thing, but different -- fresher, with a bit of crunch, and more alive.

"One of the things we would like to do at the farm is to educate the public that healthful eating does not mean sacrificing taste nor time," said Ms. Shannon, who is married to performance artist Bill Shannon. He is the son of Randa Shannon, co-owner of Mildreds' Daughters with Barbara Kline.

As Ms. Shannon demonstrated with her buffet lunch in the farm's strawbale barn, raw foods artfully prepared can be exceptionally beautiful, with deep, rich, vibrant colors undiminished by frying, boiling or baking. That's evident in raw food cookbooks, too, which have found their own niche on bookstore shelves.

"Raw Food/Real World" features color close-ups of such luminous dishes as ravioli made from thinly sliced red beets stuffed with cashew cheese filling and topped with a glaze of yellow bell peppers. Among the jewel-toned soups in Charlie Trotter and Roxanne Klein's "Raw" cookbook, published in 2003, is a lime-colored English Cucumber Soup garnished with a ring of mayonnaise made from pine nuts.

Raw foodists definitely are a lot nuttier than most people: Nuts are the adaptable workhorse of raw food cuisine, used to make substitutes for noodles, meatballs, pestos, cheese, rice and pastry.

Ms. Shannon passed around a plate of rattlesnake beans in their edible pink-and-green pods and strips of carrots, celery and red pepper, all radiating from a cup of strangely familiar dip whose ingredients were hard to pin down.

She broke the suspense: It's raw cashews soaked in water for an hour, then blended with ranch dip seasonings in a food processor. Soaking nuts softens them and helps break them down for use in many raw food recipes. But soaking takes time -- and forethought.

"I sometimes make meatballs from walnuts when I actually have time to plan ahead," Ms. Shannon said. The walnuts must be soaked four to six hours.

Marinating, used to soften vegetables, provides an outlet for experimentation and creativity. With limitless combinations of ingredients, marinades also introduce more variety to a diet built only around plant foods.

But first the veggies have to be chopped.

"What I find most inconvenient about raw cooking is it's a lot of prep," she said.

But on the plus side, as Ms. Katz points out, "You don't have any pots to clean up. And everything can be prepared a little in advance if you're having people over."

"As good as this looks, I'm not sure they've convinced me it's easy," Lou Fineberg of Bloomfield said after the class, which he joined to learn more about the health benefits of raw foods.

Ms. Shannon thinks it's well worth the effort, and never more so than in late August, when the farm's organically grown bounty is irresistible, when the heirloom tomatoes, beans, zucchini and red peppers are so fresh they practically beg to be eaten just the way nature offers them ... in the raw.