My thoughts on this, for whatever they are worth, have very little to do with the RAW but rather with the ideas behind the rules...
Creating nourishing food or water isn't a matter of spell duration. It's a matter of creating the "mystical" property of food and water that makes it nourishing. Magically created food and water with a duration is, by it's nature, a temporary thing sustained by magic which ceases to exist when the magic ends. It lacks some essential property necessary to make it real and therefore it cannot nourish like real food and water. Whatever nourishment is gained from it is temporary and ends when the magic ends. Food and water created by ritual magic is real.
Examples of secondary effects like temporary magical fire burning or temporary magical horses leaving hoofprints are not equal to temporary food nourishing because nourishment is a more complex mystical function than burning or leaving hoofprints. Ultimately, nourishment is a life-giving property, equal to healing, and magical life-giving properties, like healing, require ritual magic.
IMO.
(Yeah, I just copied and pasted this from the last thread where Direwolf75 and I disagreed on this point. 
)