I work shifts too- it can be really tough.
When I'm on days, I take in soup/mugshots or a salad. I'll often take fruit to snack on too. I often put something in the slow cooker before I go out so when I come back I don't just grab anything and everything!
On afternoons, I may take in the evening befores left overs. Like spag Bol or chilli and throw it in the microwave. I always make sure before afternoons that I have a fairly filling meal like a slimming world style 'fry up' because I never know if/when I'll get to eat my meal.
On nights (don't think you do these though) I take in cereal and fruit as it's really refreshing in the early hours!!
Hope this helps a little. X