Can you not prepare something the night before and take it with you? The magic porridge seems to be a popular choice. You can just take a tuperware bowl and spoon. Pasta is easy to eat on the run too. I do tubs of the stuff (pasta, 14 olives 1syn, tinned baby corn, spring onion, cucumber, red/yellow pepper, cherry tomatoes, with x2 tbsp extra light Mayo 1.5syns and a spoonfull of natural yoghurt) massive lunch for 2.5 syns on a green or EE). It's been my life saver, cos it keeps well at room temp, so I can just munch wherever I am!!
Preparation the night bEfore is what keeps me in track the following day.
Good luck xxx