This is a sci-fi cliche that gets more nonsensical the more I think of it. Like... our meat has the same taste and consistency as that of pigs, which produce more meat, grow faster, have less strict nutritional requirements to reach eating age, and reproduce faster than humans. Besides that, any race advanced enough to bridge the space of stars to reach Earth must surely be advanced enough to produce their own preferred food in abundance! The only reason any alien race would be interested in us for food would be pure bloodlust, which isn't how most of the "to serve man" crowd is portrayed. It's just... silly. Just wanted to vent.