What's In Fast Food? Here's The Secret

We've all felt it! That irresistible urge to go into a fast-food restaurant after catching a whiff of a delicious smell. But many of the secrets being used to entice customers come straight out of the lab instead of hot off the grill.

Millions of Americans grew up enjoying burgers, shakes, and fries. We all know that fast food is not the healthiest choice. But it is fast.

So many Americans eat fast food that it averages out to three burgers and four orders of fries per person per week.

A new fast-food restaurant opens in the United States every two hours.

The food may be fast and easy, but there's nothing simple about what goes into it.

The moment patrons walk in the door, they are hit with lab-developed smells.

"The industry as a whole is piping in the aromas above the door. They pipe it in above their doorways so you get a hit of it as you walk in. It makes you start to salivate," said Sheila Moore, a chemist who created many of the fast-food smells we know and love.

Her clients include McDonald's, Wendy's, Burger King and Pizza Hut.

Did you ever wonder why fast food tastes lousy when its re-heated?

The flavor and smell texture coatings aren't designed to last after the initial cooking process.

"There's lard or beef fat flavor that goes on McDonald's french fries. Burger King has their own. It also goes through a sugar bath before they're fried," Moore said.

But do you want to know what's in it, other than fat that makes it taste so good?

A lot of it is lab-developed flavoring.

"This is a jar of strawberry flavor," Moore said as she held up a jar.

"You'll probably find very little real strawberry in a strawberry shake, but you will find lab derived flavor crystals," Moore said. "As soon as you smell it you think of a real strawberry as though you just picked it and were eating it," she said.

It's these tricks of the trade that keep millions and millions of Americans coming back for more.