Can you eat like a king on 600 calories?

That’s the premise of the just-opened LYFE Kitchen in Palo Alto, the first restaurant of a new chain devoted to healthy eating.

Founder Stephen Sidwell, 48, a slimmed-down investment banker, decided it was ridiculous to demand that diners exercise willpower when eating out if there aren’t convenient, good-tasting alternatives to 2,000-calorie entrees and 1,200-calorie desserts.

He brought his idea to two veterans of the “fast casual” restaurant sector, former McDonald’s executives Mike Roberts and Mike Donahue, who hired two top chefs to create the dishes and perhaps kick-start a movement. One was Southern food aficionado Art Smith (he was Oprah’s private chef), who has reformed his fried-chicken-eating ways, losing 100 pounds in the process. The other was Tal Ronnen, a vegan-vegetarian celebrity chef and author of “The Conscious Cook.”

The result? Every dish — from the grass-fed beef burger to the whole grain-crusted eggplant Parmesan — is under 600 calories. Many are far less. The grilled barramundi with vegetables in a wild mushroom broth is 263 calories. Vegan, low-sodium and gluten-free choices abound, and the produce is grown locally. No dish costs more than $12.99.

“I was doing a lot of traveling — fine dining at night, fast food during the day — and gained a lot of weight,” Sidwell says, so he tried a diet program of prepared meals. The overly processed food gave him headaches. Then Sidwell hired a personal chef. The family all loved the food, and he dropped 35 pounds.

Then it occurred to him: “Why can’t I buy this kind of food?”

So Smith developed recipes such as Art’s Unfried Chicken, baked chicken breast served with roasted squash, Brussels sprouts, dried cranberries and Dijon vinaigrette. And Ronnen came up with Tal’s Ancient Grain Bowl: stir-fried Gardein (meat substitute) and vegetables atop whole-grain quinoa and farro.

“It’s all about choices,” says chef Smith, who — during a summertime visit to Palo Alto — managed to fit in a trip or two to the Peninsula Creamery because he had eaten healthfully otherwise. “Why not enjoy a vegan dessert and feel good about it?”

Although LYFE — Love Your Food Everyday — Kitchen is based in Chicago and Sidwell lives in Vancouver, B.C., the executives tapped Palo Alto for their first location because they figured innovative, health-conscious residents there would be quick to embrace their concept.

The Peninsula response will determine how quickly the company expands. Already, Roberts says, the LYFE team has overcome a lot of “you people have lost your minds” naysayers on the way to last week’s opening.

The company next plans to launch its own line of grocery store products (ready to eat, frozen and bakery) in the next few months, then open more Northern California locations before expanding into Southern California. The goal is several hundred restaurants within five or 10 years.