When I work long shifts I ensure I eat little and often and keep close eye on my blood sugar! I also make sure after a night shift I have breakfast (normally 2x slices of peanut butter an jam on toast) before I go to bed. I don't know what your job entails but if you can, make sure you eat small snacks and carry your monitor around with you to check regularly. In what way do these shifts play havoc on your sugars? I don't find shifts effect me too bad although I often run a little higher when in work for some reason!