Welp, this kid, whoever he is, should definitely not eat more.

"Yeah, sure!" Gold says, and grabs the kid's hand so he won't run off on him, having no intention of letting him eat cookies before figuring out what kind of an effect he's under. It doesn't seem like the lying effect Gold got, so it's gotta be something else. "Which ones didn't you eat?"

A question can't be a lie, but Gold goes with opposite speech just in case it'd get twisted anyway.