Man, I feel so much better if I scoff junk on nights. 
To keep me in plan with my silly shift pattern, I officially start my slimming world days at 6am, so my healthy extras and syns can be eaten between 6am-6am. I did this to avoid accidentally having extra syns HEs on first/last nights. 
I always have a big bottle of water with me. I take a proper hot meal with me, like soup and bread or curry and rice. Before I go to bed when I get home, I have cereal or porridge. Before going on shift, I have something  'brunchy', like beans or scrambled egg on toast. I always take fruit, yogurt, cereal bars or syn chocolates, like roses, to keep me going.