It is so much easier for me when I do it at work. Mentally I just know there is no food, so I don't really give it another thought. Even if I am bored out of my mind (as is often the case) there is no food so I can't fall back on that.
I also think a good UD is the best lead in to an easier DD. I will do MD tomorrow as well. But again it is a work day so food before 4:30 is not really an option.