“I know what you’re thinking,” says MythBusters co-host Grant Imahara, standing in front of a conveyer belt chugging out french fries. “These look like potatoes, but are they really potatoes?”

Such is the question many people find themselves asking about McDonald’s signature french fries.

And so, as a part of the fast food chain’s new honesty-is-the-best-policy marketing campaign, consumers are getting a firsthand look at the assembly process.

“Are the fries even made out of potatoes? Are they ground up and mushed into the fry shape?” Imahara asks.

Mickey D’s apparently has the answers.

Read next: Watch McDonald’s Prove the McRib is Made of Actual Food

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