They are asking for double -- at least.

Fast food workers from all around the country are asking for a raise in the federal minimum wage, from the current $7.25 per hour to $15 per hour.

Walkouts and protests were planned in more than 100 cities Thursday. Workers say the current minimum wage is not enough to live on.

"If you work 40 hours a week, 52 weeks a year, you'd make $15,000," explained Sherry Kasper, an economics professor at Maryville College. "And the poverty threshold in the United States for a family of two is $15,000. So, the living wage now is not really the living wage that it was started out to be."

Kasper explained, the minimum wage system started in the 1930s as a way to set a base pay that people could live on. She said it's been raised occasionally, but not much in the past decade.

Recent protests like those today intrigue her.

"Minimum wage workers are not very powerful people in the economy. They're all getting together and protesting and they're finding the time to do that... [it] is kind of amazing."

UT student groups planned to host a similar protest in Knoxville, by staging a flash mob at the McDonald's on Cumberland Avenue. Their first attempt to meet during mid-day was a bust, drawing just one participant who left when nobody else arrived. Organizers say they had scheduling conflicts with students, and expected to try again later in the day.

"I'm not really surprised," said Joe Burger, whose family owns that McDonald's franchise, and others locally. "It's something going on nationally. We haven't really seen much activity in Knoxville."

Burger says many of his employees quickly move past minimum wage.

"Just because we hire somebody at minimum wage, they don't stay there very long," he said. "There's an opportunity to advance."

He adds, "We try to find out who's here just to make a few dollars on the side as a second job or as a single person who maybe just wants to work during dinner, and who really wants a career."

He said raising the minimum wage to $15 per hour wouldn't be sustainable, because all other wages would increase, too.

However, that's what protesters are asking for, which would bring the yearly salary for a full-time worker to about $30,000.

For comparison, a new Knoxville police officer who just graduated from academy makes about $32,000. The Knoxville Fire Department says starting salary for their firefighters totals about $30,000. The Knox County school district pays entry level teachers with a bachelor's degree about $35,000 per year.

Dr. Kasper says changing minimum wage requires action from Congress, and isn't an easy thing to do.

"There have been all kinds of studies done about this, therefore there is evidence on both sides. Sometimes [raising minimum wage] doesn't cause unemployment, other times it does," she said.

"So it is a controversial subject because research supports both sides."