I think it is a conditioned response. But with the stipulation that almost everything is. I never crave natto, or caviar, or haggis. Maybe if I'd ever been exposed to any one of these, I'd crave them. Hard to crave something you've never met. But in this is that conditioned responses rely on unconditioned, if we didn't have a natural appetite for salt, sugar, fat, protein etc., pairing these with particular stimuli wouldn't condition a response.

A conditioned response doesn't necessarily involve daily craving. There are certain foods I pretty much crave only around Christmas. Like rutabagas.