An order of roasted salmon with vegetables and miso  at LYFE Kitchen in Palo Alto, Calif.: 596 calories, 931 milligrams of sodium. (LYFE Kitchen/LYFE KITCHEN)

Okay, it was bright green. But that was the only clue that the kale-banana smoothie I was sipping included a cup of kale leaves and was certifiably “healthy.” The only tip that my chicken, served alongside a medley of baby Brussels sprouts, butternut squash and dried cranberries, was good for me was that it had noticeably little salt. Had I been served the chocolate budin in a fashionable Washington restaurant, I never would have guessed that it had just 211 calories.

And that’s the way LYFE Kitchen prefers it, even though the new fast-casual chain has strict nutrition and calorie standards: At LYFE (the acronym stands for “Love Your Food Everyday”) the kitchen uses no butter, no cream, no white flour, no high-fructose corn syrup, no trans fats, no additives, no preservatives. Every dish, from the fish tacos to the grass-fed hamburger, has fewer than 600 calories and no more than 1,000 milligrams of sodium. “We don’t sell health,” says Mike Donahue, the company’s chief communications officer. “We sell taste.”

The strategy is part of a broader trend, dubbed “stealth health,” in the restaurant industry. Along with LYFE, there are vegan restaurants Veggie Grill and Native Foods Kitchen, Seasons 52 (from Darden Restaurants, which owns the Olive Garden and Red Lobster) and Energy Kitchen, which serves lower-calorie burgers and shakes and opened its first District store in January. The trend is based on an obvious truth. While most of us say we would like to eat healthfully, we really don’t want to give anything up, especially when eating out. According to research firm Technomic, about half of consumers go to restaurants to indulge or treat themselves. The sad fact is that in most people’s experience, healthful food — tofu, brown rice and low-fat whatever — is the opposite of delicious.

I was particularly interested in LYFE Kitchen because its aim is to change that unhealthy and peculiarly American perception. (Only in the United States do people consider eating nutritious and nourishing foods an obligation.) Created by a team of former McDonald’s executives, LYFE sources mostly organic and local ingredients and serves them up in sensibly sized portions of, say, corn chowder and grilled barramundi with soba noodles.

Art Smith, former Oprah chef and owner of Art and Soul restaurant on Capitol Hill, designed the menu along with vegan chef Tal Ronnen. There are some soy proteins; Gardein brand “beef tips” top the “ancient grain bowl” of whole-grain farro and quinoa. But for the most part, the dishes showcase real food — 100 percent grass-fed beef, fish such as mahi mahi and salmon, and lots of kale — and make good use of fresh herbs, coconut milk and cashew cream to deliver big flavors without excessive calories or sodium.

I visited LYFE Kitchen this month at its first outlet in Palo Alto, Calif. It’s a beautiful space, with oodles of natural light, an herb wall full of lemon grass, lovage and marjoram and enough eco-friendly bamboo and recycled wood to cause it to be mistaken for one of those high-priced farm-to-table restaurants up the road in Berkeley. The messages on the menu are deliberately subtle. There is no preaching about organic or sustainably sourced ingredients, no justification for why you won’t find Coke or Pepsi. Instead, there is a list of options and, in small gray print underneath, the number of calories and total sodium in each. The Art’s Unfried Chicken that I tasted had 518 calories and 625 milligrams of sodium. The roasted mushroom and goat cheese flatbread has 585 calories and 810 milligrams of sodium.

“We don’t want to be in your face,” Larry Taylor, LYFE’s vice president of systems and franchises, told me over a plate of grilled artichokes and garlic aioli that had been lightened with Greek yogurt. “Some people might be nervous to come into a healthy restaurant. They might be embarrassed if they think they might be surrounded by a bunch of foodies. We don’t want to intimidate.”

Seasons 52, Darden’s casual dining concept, has made a similar calculation. Like LYFE Kitchen, it limits calories and uses neither fryers nor butter. True to its name, it changes its menu with the seasons and offers specials each week that incorporate a bumper crop of strawberries or the run of Copper River salmon. The top of each menu reads: “Seasonally Inspired with every item under 475 calories.” But executive chef Clifford Pleau insists that servers mention the standards only once. “We tell them, ‘If you say it at all, you say it once, and never, ever at dessert.’”

LYFE and Seasons 52 are proving that stealth health has broad appeal. Seasons 52 opened 10 new restaurants last year, bringing its total to 32 outlets in 16 states (including one in North Bethesda and one in Tysons Corner). LYFE has made a splash in Silicon Valley. Its first year, it sold 13,000 pounds of Brussels sprouts, a vegetable that chief executive Mike Roberts has sworn to transform into the next french fry. The restaurant beat its revenue projections of $2.4 million by 25 percent. LYFE Kitchen plans to open eight more restaurants in California this year — you can’t fault it for trying out a sure-thing market first — and 250 over the next five years. Cities on the short list include Chicago, New York and the District.

I didn’t love everything I tasted at LYFE Kitchen. The flatbreads, made with whole-wheat flour and flax seed, tasted, well, healthful. And although I loved the freshness of the dishes, I wondered whether the lack of salt would turn off regular customers of McDonald’s or the Olive Garden. But perhaps the biggest potential glitch in LYFE’s plan for 21st-century food domination is the price. LYFE is not exclusive. But it certainly costs more than dinner at Chipotle or Energy Kitchen. Art’s Unfried Chicken, LYFE’s biggest seller, costs $12.99. The (delicious) sustainably raised Scottish salmon, served with bok choy and shiitake mushrooms, costs $14.99. And it’s easy to spend more when you order a glass of biodynamic wine or a house-made ginger-mint soda.

“It was a little expensive,” said Tori Pennings, a 23-year-old grad student in education at nearby Stanford, who had come for the first time and ordered the $8.99 beet-and-farro salad. “But I like that it’s quick and healthy.”

LYFE is counting on lots of people having the same willingness to pay for that alluring combination of healthful and convenient. It certainly has worked for Whole Foods Market. Despite its nickname “Whole Paycheck,” the grocer saw sales rise 14 percent, to $3.9 billion, in its most recent quarter. As prepared foods make up nearly a quarter of Whole Foods’ sales, I’m betting that the prospects of a guilt-free meal you don’t even have to heat up in the microwave are pretty good. Pass me another kale-banana smoothie.

Black, a former Food section staffer based in Brooklyn, writes Smarter Food monthly. Follow her on Twitter: @jane_black.