A tree grows in Friendship Heights? It's not real, but the gnarled roots and weathered bark make you look twice--just as the cooking at Rock Creek is more and less than meets the eye. Photographs by Kathryn Norwood.

An oak tree canopies the dining room at Rock Creek in DC’s Friendship Heights. It’s not real, but with gnarled roots and weathered bark, it makes you look twice.

Rock Creek’s kitchen engages in a similar sleight of hand, turning out food that’s good for you even if it tastes as though it might not be. Given the restaurant’s health-conscious philosophy—every entrée has fewer than 500 calories—this is no small feat. Despite a “no butter, no cream, no sugar” edict, most of the cooking could pass muster in any fine-dining room. And much of it is delicious.

Judith Hammerschmidt and Tom S. Williams, who opened Rock Creek Bethesda in 2005, have gone splashier—and pricier—at the Mazza Gallerie outpost. Light streams into the circular dining room from windows overlooking Wisconsin Avenue. Ochre velvet circular booths are a backdrop for the lifelike tree, built by NatureMaker, the California steel artisans who created the Frenchified arbors at the Las Vegas casino Paris.

Impressive as these design elements are, the place is brought to life by the irrepressible Ralph Fredericks—formerly of Famoso—the maître d’ who greets moviegoers (the Mazza cinema is next door) and neighborhood couples who stop by.

Ris Lacoste, longtime chef at 1789, was brought on to consult, taste, and mentor; she’ll be overseeing Rock Creek Bethesda’s menu as well. But it’s executive chef Ethan McKee, former sous chef at Equinox, who’s behind the dishes on this seasonal and market-driven New American menu.

From the gratis tastes that begin a meal—a pretty dish of red and yellow cherry tomatoes kissed with herbed olive oil, a crunchy French breakfast radish tucked beneath, and a basket of pepita-crusted bread—to starters and main courses, restraint is the word here.

Brined and slow-cooked for four hours, Rock Creek's roasted Amish chicken with tarragon-infused jus is among the homiest and best plates on the menu.

Portions are large enough to satisfy but not to stuff—though you might be tempted to order seconds of the gently crisped potato gnocchi, scattered atop a mound of ratatouille, or the delicate soft-shell crabs married with artichokes and piquillo peppers.

Most plates are so full of color and verve that you don’t miss the butter and cream. Grilled quail gets a bed of bright greens and magenta beets. Baby lettuces are garnished with Medjool dates stuffed with goat cheese and crusted with hazelnuts. The curiously named pacu “ribs”—a bar-menu snack that often shows up as a special in the dining room—is pure fun: This Brazilian freshwater fish comes sliced to look like a miniature rack of baby backs; the best way to eat it is with your hands, as you would ribs.

Main courses yield plates such as tender grilled veal medallions with semolina cakes; pan-seared black sea bass set against a palette of baby spinach, fennel, and red-pepper coulis; and grilled diver scallops, shrimp, and mussels in a subtle coconut curry. Grilled wild Alaska salmon has a cooked-too-long taste; even a bright black-bean succotash and green-tomato chow-chow can’t make up for it.

Most endearing of all is the homey roasted Amish chicken with tarragon-infused jus. Brined and slow-cooked for four hours, it’s as moist and flavorful as you could hope for. Fingerling potatoes, baby spinach, corn, and olive-oil-slicked, oven-roasted tomatoes make for a stellar plate.

Desserts such as this trio of one-bite wonders are health-conscious--and delicious.

Dessert could be the downfall of a health-minded eatery. Bad enough that cream and butter are all but banned, but sugar? Both the Mazza and Bethesda restaurants use a new natural product called Whey Low that tastes and bakes like the real thing—mainly because it is sugar, but as engineered by Maryland biotechnologist Lee Zehner, a teaspoon has one calorie, compared with 50 in regular sugar, and just one gram of carbs.

Which means desserts for the most part don’t disappoint. Pastry chef Roger Potter’s ice creams and gelati—including chocolate-caramel, apricot, and honey-vanilla—are as creamy and luscious as you’ll find anywhere; they come with tiny cookie adornments. The Greek-yogurt sorbet could become an addiction. And lilliputian one-bite wonders—a nicely tart lemon-meringue bar, crumbly peach upside-down cake, and a chocolatey peanut-butter bar—make an attractive tableau.

Think of dessert as a convincing closer. Eating at Rock Creek is about all that is possible—not about going without.