Chick-fil-A has banned one ingredient from its restaurants

Chick-fil-A is continuously tweaking its menu to come up with new dishes and cycle out old ones.

The company employs six chefs, who work out of its test kitchen in Atlanta, to experiment with new ingredients for potential menu items.

Lately, the chefs have been focusing on coming up with new salads and healthy sides, such as the recently launched superfood side with kale and broccolini.

Chick-fil-A's chefs are free to experiment with all kinds of ingredients, except for one: iceberg lettuce.

"We have a mandate: never use iceberg lettuce," David Farmer, Chick-fil-A vice president of menu strategy and development, said in an interview from Chick-fil-A's test kitchen.

Farmer claims iceberg lettuce is tasteless and nutrionless, which is why he says he's banned the ingredient.

"It's at the bottom of the salad food chain," he says. "There is no nutritional value in iceberg lettuce."

Farmer said he's more supportive of nutrient-dense greens like kale.

"Our focus over the last couple years has been around health," he says. "We're seeing purchase behavior shift toward healthier items, so we're fully committed to providing more nutritional options for customers."

Farmer says he gets some inspiration for new menu items from frequent trips to New York.

"I travel to New York to check out new concepts and walk around trying food all day long until I can't stand to put anything else in my mouth," he said.

Chick-fil-A also keeps an eye on its competition, which includes traditional fast-food restaurants like McDonald's and Wendy's, as well as fast-casual chains like Panera Bread and Chipotle.