ABC News' Elizabeth Stuart reports:

Uno's Chicago Grill, home of the original deep-dish pizza, is flipping casual dining on its head.

The idea: prepare some of the less healthy items in a more nutritious way - like pizza with multigrain crust - and other healthy alternatives.  As a result, the company has been recognized by Health magazine as the "Healthiest Chain Restaurant," a surprising honor for a pizza restaurant.

Company CEO Frank Guidara told "Nightline" anchor Cynthia McFadden they are constantly trying to upgrade the quality of what they serve.

"Every item on (our) menu has gotten a review in terms of ingredients, and they are the healthiest ingredients," he said. "Like a French fry. Our French fries, we were the first to make them with trans fat-free oil. If you want a French fry, have Uno's."

"A third of all meals are eaten at casual dining restaurants," Guidara continued.  "When I joined Uno's my attitude was casual dining restaurants are terrible.  I don't even eat in casual dining restaurants.  Why would I take over a casual dining company?"

The bottom line answer is that "healthy" turns out to be good for business.  In fact, Uno's had a banner year last year making $390 million dollars, says Guidara. Pizza alone is a $30 billion industry, with over three billion pies sold in the U.S. every year, according to the National Restaurant Association. That's 46 slices a year for every person. But Uno's is determined not to be your grandmother's pizza joint. Its menu now features a wide array of non-pizza choices.

"Nightline" was in the restaurant's test kitchen outside of Boston a few weeks ago as Executive Chef Chris Catto cooked up a few new items for this summer's menu, including a summer salad with oranges and almonds, and salmon with chimichurri sauce.

"Nightline" anchor Cynthia McFadden in Uno's Chicago Grill's test kitchen near Boston, with company CEO Frank Guidara and head chef Chris Gatto. Credit: Cynthia McFadden/ABC

But despite many positive changes, the way the company deals with calories raises concerns for some customers.  Calories counts are not listed next to food items on the menus.  Guidara had kiosks installed in the front of each restaurant listing in detail all the nutritional content of each dish - including calorie counts - but the information is not always clear.  For example, a small cheese and tomato pizza is listed as 580 calories. However, this is actually 580 calories per serving, and there are three servings per pizza. In other words, if you eat the whole pizza, it's over 1,700 calories.

Guidara concedes such listings may be confusing and says some changes may be needed.  But he points out the nation's obesity problem is in part propelled by the amount some consume.  He hopes that by listing the portion sizes some customers consider sharing meals or taking portions home. In essence, he insists, it's about providing choice.

At Uno's, Guidara says,  they want to make sure there is something healthy and tasty on the menu for everyone.