Those who have been returned home and then brought back to Vallo seem to indicate that it was as though no time had passed while they were here. The prevailing theory tends to err toward us being plucked from our previous timelines or worlds and deposited here, but a version of us still exists in the original. To those still there, we are living our lives as normal as though we have never left at all.
And yes, there are certain types of magic that I could do easily back home that I'm unable to do here, at least to the grander scope that they can usual entail.
I'm unsure what sort of food you're referring to in your final question, so I'm less helpful on that front.