People hold signs during a protest for better wages for fast food workers outside a McDonald's restaurant in Harlem on April 4, 2013 in New York City. - 

Fast food might not be all that fast in a bunch of cities Monday. Thousands of fast food workers are expected to walk off the job, demanding more hours and a wage of $15 an hour. A similar strike occurred earlier this year, but this time fast food employees will be joined by retail workers in cities like Chicago and Milwaukee.

You might not think a clerk from Macy's or Victoria's Secret has much in common with someone who flips burgers. But they do, says Burt Flickinger, who directs the Strategic Resource Group.

"In retail as well as fast food, many workers have gone from full-time middle class to part-time and often moving to food stamps and below the federal poverty line," he says.

Macy's and Victoria's Secret tend to pay more than places like Walmart. But Flickinger says wages and hours have sunk across the retail industry in recent years.

Still, most folks out protesting will be fast food workers like Kareem Starks. He makes $7.25 an hour at a McDonald's in Brooklyn. Economists are skeptical consumers will pay more to support higher fast food wages, but Starks disagrees.

"People love McDonald's; people love fast food. If they raise the prices, by all means, people are still going to buy it. It's not going to stop people from eating," he says. "But it will also help us live a better life than what we living now."

In a written statement, McDonald's said its workers are paid competitive wages and have opportunities to advance.