I think the OP's main concern would be being hungry while at work, My mum was a school chef, and it's very hard work, plus you are surrounded by all the things you no longer should eat, which is pretty hard going. You're not allowed to eat while working and really, it's all often so carby, you just shouldn't, but by the time you leave work you have been exposed to all those carbs, including endless desserts, that you brain is not functioning straight. Some of us go into self-destruct when hungry and just eat anything. It's no good trying to be good. Your brain just tells you to s*d it!
Good luck trying ways around this Aqualung. It's quite hard, but my gut feeling would be to go in feeling satiated, ad maybe have something in the car to nibble on while going home. That was always my worst time and I'd end up in a garage buying a cheese pastie.