I have never been convinced that the hunger pause is actually tied to the cookpot. This explanation is more plausible to me (roughly: the hunger pause is proportional to the highest nutrition value in the last bite you ate, but most things you would eat before getting a cookpot aren't high enough to really notice it). Pies certainly do pause hunger, I've watched the hunger value drop at a roughly consistent rate in the character pane and then stop dropping after eating a slice of pie, at least in the immediate term. If the linked theory is correct, a red meat pie slice should have the same hunger pause as a 2x red meat + 2x vegetable stew, which is something I vaguely want to test sometime but I'm not sure if I could measure accurately enough.
The relevance to spices is that spices can't apply the "special cookpot effect" to other things, because there is no special cookpot effect. Applying a multiplier to the hidden-hunger-pause-nutrition might be plausible but without making it un-hidden it would be hard to explain what benefit the spices were having, though?