GOD WILLING, 2013 will go down in history as the year chefs emerged from the haze of fat-forward cooking, rubbed the lard from their eyes and discovered all the flavor they were missing.

Anyone who has logged time tableside at America's trendier restaurants can attest to the full-throttle bender on which chefs have escorted diners in recent years. The cooking aesthetic I'm talking about is summed up quite evocatively in a term coined a couple of years ago by the food writer Josh Ozersky: lardcore. Deep-fried pig tails. Bacon deviled eggs. Marrow bones the size of hockey sticks. Foie gras doughnuts. The list goes on. Then there are the rivers of butter and cream that course through these meals unseen, basting meats and fish, thickening sauces or simply as an insurance policy whenever a dish's oomph is in doubt.

Cathal Armstrong, chef-owner of Restaurant Eve in Alexandria, Va., has been among the first to cry "uncle." After joining first lady Michelle Obama's "Let's Move!" campaign against childhood obesity and subsequently shedding 50 pounds of his own, Mr. Armstrong set his sights on his restaurant guests: Shouldn't they benefit from the same nutritional standards he sets for himself and his kids? So Mr. Armstrong began tinkering with preparations and proportions, experimenting with trading the calorie-dense and nutrition-light for more nourishing fare. In the process, he discovered that the flavors he could achieve without all the fat and salt weren't just passable; they were actually better.

Take carrot purée, which would traditionally be made by simmering the vegetable in liquid, then puréeing and layering in butter, cream and salt. Now, Mr. Armstrong uses the sous-vide method—sealing the food in plastic and submerging it in a low-temperature water bath—to cook carrots slowly in their own juices, concentrating their flavor to create a pungent carrot mousse that runs rings around the classical version. "Using lots of butter is the way we all learned. We always said 'fat equals flavor,' " Mr. Armstrong explained. "Well, it does, but there are other things that have flavor, too."

With that in mind, Mr. Armstrong has quietly transformed Restaurant Eve into a prototype for healthy high-end dining. Sauces thickened with butter and flour in the old French style have been replaced by lively vinaigrettes and clean, protein-rich meat stocks. House-made Greek yogurt is used instead of cream. Game meats like venison and antelope, with their earthy complexity and low fat content, have become go-to ingredients. Rib eye is still on the menu, but it's grass-fed (and therefore leaner), the portion is smaller and it's served alongside an appropriate complement of vegetables. The restaurant doesn't charge guests for water (still or sparkling), which Mr. Armstrong believes is vital to a balanced diet.