"Who wants to go to a fast-food place that doesn't have french fries?," asks my second-grader, rolling his eyes. "That's not a fast-food place," he adds indignantly.

I've just told him we're going to eat at a "natural fast-food restaurant" called O'Naturals. I usually know how to make virtuous field trips like this one sound enticing, but in this case I'm so excited about the concept of O'Naturals that I've forgotten to put a kid-friendly spin on the situation.

Still, he has a point. How can it be "fast food" without fries, burgers and diet Coke? I tell him that O'Naturals, which opened in Acton last February, is not a fast-food joint at all. More accurately, it serves slow food, fast.

O'Naturals, the brainchild of Stonyfield Farm's yogurt guru Gary Hirshberg and his partner, Mac McCabe, serves healthy, sustainably grown food at excellent prices in due haste. They source local and organic products whenever possible, use environmentally sound construction materials, and encourage community-building by regularly offering table space to local non-profits, then donating 10 percent of a day's proceeds back to the group.

There are currently four O'Naturals (the other three are in Maine), but ultimately, McCabe hopes to have stores across the nation. "Our plan is that we're going to be the natural foods alternative to fast food chains."

Other than those fries and burgers my boy craves, there are a few other things O'Naturals doesn't have: diet sodas, Styrofoam, plastic  flatware and harsh chemical cleansers. Walk into the Acton branch, and you'll notice that while it has that pleasantly cavernous fast-food feel, it doesn't have the usual stale stench, greasy floors and hard plastic furniture. Instead, it's sparkling clean. It has a kids' play space, high chairs, and even couches for canoodling.

But how's the food? On the whole, happily, it's great. The menu comprises soups, salads, noodle dishes and flatbread sandwiches. (The flatbread, baked on-site throughout the day, is enough to turn bread fanatics into instant regulars.) Natural sodas, though lacking the usual preservatives found in regular soda, taste refreshingly unhealthy.

Clam chowder, served on Tuesdays and Fridays, is rich, thick, and brimming with potatoes and clams. In fact, all the soups we try -- chicken vegetable, lentil, squash/apple bisque -- are thick and flavorful and would make hearty, comforting winter meals.

The salads, too, are fantastic, with ultra-fresh greens and delicious homemade dressings (including balsamic vinaigrette, ranch and vegan Caesar). All the hot, cooked-to-order noodle dishes win me over, but my favorite is the Chap Chae (soy-based "glass" noodles), which is both salty and sweet, with pieces of wild Alaskan salmon tossed on top. Other add-ins include chicken, smoked tofu, steak and salmon. The steak sandwich, meaty and tender, is simply delicious.

As for dessert, Belgian chocolate chunk cookies are good enough to fight over, and a cup of (organic) Equal Exchange coffee with (organic) cream makes a fine end to a meal.

There are a few items on the menu that I wouldn't order again. Wild bison meatloaf is a little too wild for me, though it's probably an "acquired taste." The flabby, tasteless hot dog is a "not dog" in my family (as in "we're not eating that dog"). Baked chicken tenders are tasty, but not crisp enough.

Still, it's uplifting to walk into a fast food-style restaurant knowing that the meats are antibiotic- and hormone-free, the veggies are organic and local whenever possible, and that the owners' goal is to impact the environment as little as possible and give back to local communities as much as possible. If this is what the future tastes like, I say hear, hear. In fact, I propose a toast (of natural soad and fairly-traded coffee): to O'Naturals. May it prosper and multiply -- to my town next, if I may be so bold.