When I was working in an office, I used to take packed lunches every day, and they were usually very simple, minimum prep. More a case of standing in front of the fridge door tipping food into my wee insulated lunch bag, than actually preparing anything...

I love food, but my goal is always to spend as little time in the kitchen as possible, while getting the best quality, flavour and nutrition possible.
My typical lunches were:
- a blob of mozzarella and a beef tomato, with olives
- a chunk of crustless veg and ham and goatscheese quiche (yes, I made that one, but it only took about 10 mins prep, cooking time, and then got chopped up into the freezer for defrosting. so I would let it defrost all morning, then eat it at lunchtime)
- cold meat, cold cheese, tinned fish, plus mayo, cherry toms and any saladings that were handy
- whole avocado and lemon juice, eaten out of the skin with a teaspoon. Had one of those mini lemon squirts in the fridge at work
- greek yogurt and frozen berries (again, defrosted by lunchtime)
- I went through a phase of eating hummus (with a teasp), but it was a bought one, and I didn't want all that veg oil, so I stopped
- sometimes a bag of Posh Pork Scratchings (no junk in them) was enough
- I always had a 9Bar in my bag, in case of lows, or hunger, or traffic jams, or any of life's hiccups. For me, Peanut 9Bars have minimal bg impact, and have got me out of quite a few scrapes, since they stop my hypos in their tracks, but never bounce me our of ketosis. Wonderful wee things.
Nowadays, I often skip both breakfast and lunch, or just have a coffee with cream in it. I find the cream is perfect - no blood glucose impact, sustaining, satisfying, and as much or as little as I want. It is very reassuring to know that I can always ask for that as a fallback option, even in place of a meal, if necessary.
