I've discovered a new lunch this week thanks to a gym instructor friend of mine who posted a picture on facebook and it looked damn tasty!
Brown rice, how much is up to you. For the calories I gave, I use 50g of dry weight before you cook it. Can do a few days at once and bag it up seperately. (167 cals)
Veg - Asda sell a bag of 4 steam bags of carrot, brocolli and cauliflower which is what I use. (49 cals)
Chicken - some kind of chicken, I mixed some spices to make a fajita seasoning and grilled it on the george foreman, could use ready cooked sliced up chicken though. I use half a chicken breast which is about 75g. (104 cals)
Cheese sauce - sounds odd I know but it works! Gives it a bit more flavour and substance. I use Bisto instant cheese sauce granules, half of the 50ml serving. (21 cals)
So that's a total of 341 calories, only 1g saturated fat, 31g of protein, 40g carbs.
You can package it all up and shove it in the microwave for a minute and a half before you eat it or it works cold too.