That's the question that sparked a national challenge called the "October Unprocessed Pledge."
It was started by food blogger Andrew Wilder, who runs the website EatingRules.com.
He said his goal was to get 10,000 people to sign up this year, but has already surpassed that number!
Heather Philips and Stephanie Bauer are two of those people. They cleaned out their kitchens, getting rid of anything processed.
They both took the challenge last year, and are doing it again this October.
Heather said she used to eat a lot of diet foods but started feeling great when she switched to whole, natural foods.
"I feel like I am eating right, my weight was great. I feel healthier, less bloated, overall better," she said.
Wilder's website has all kinds of tips and recipes. He also told us it's not too late to sign the pledge.
"It's just a web form where you put your name and address, but there is something very powerful about publicly proclaiming you are going to do this," Wilder said.
As for what you can and can't eat, Wilder refers to what he calls "the kitchen test."
"Basically, if you could make it in your own kitchen with whole ingredients - doesn't mean you have to, but if you could - then it's unprocessed," he explained.
Stephanie says the pledge sparked her to get adventurous in the kitchen with help from EatingRules.com.
"There's recipes and everything. They pretty much break it down so it seemed easy," she said.
She said she also felt better. She had more energy and even said she lost weight.
"It falls off fast, especially if you're not used to eating whole foods," she said.
For more information, visit EatingRules.com.