Thread drift, I know, but many seem to have problems with food, so for what it’s worth, this is my method*
Before going to sleep prior to your duty, and after ironing your shirt, make a salad in a clear Tupperware box, (so the contents can be seen if required), about a 6 x 4 x 3 inch box does me, but adjust for your own requirements.
Bung in things like : lettuce, tomatoes, olives, peppers, sweetcorn, avocado, cucumber, beetroot, spring onion, mixed salad leaves, celery, artichoke, raw mushrooms etc, etc. Chop it all up** so it is easy to eat with just a fork. Don’t put salad dressing on, just a little bit of pure virgin olive oil.
For protein, you can add chopped up cheese, or prawns or ham, chicken, tuna. I put frozen prawns in - they keep the salad chilled and by the time I come to eat the salad, they have defrosted perfectly. Stick an apple, an easy peel orange, some unsalted nuts with the Tupperware in a lunch cool bag, and you have a very healthy and very tasty meal that will pass security with no problem. Pop the cool bag in the fridge until you get up to go to work. Takes about 10 mins to prepare.
Enjoy !
Anything over the liquid limit that could be hiding explosive or chemical material, such as yoghurt, chilli, curry, lasagne etc, might very well be confiscated by security. It is easy to see what is in a salad made as described.
*I often make my own food because it is much healthier than the sugar and fat laden goop we are sometimes given.
**I use kitchen scissors to chop the items straight into the box. Much easier and quicker than chopping with a knife on a board.
PS, Always carry your wallet and some cash, always carry a credit card. You never know when you might have an unscheduled night stop or get stuck down route.