3 days scran in the house keeps the looting and civil unrest held back long enough for the general population to see "something happening" be is soup kitchens or squaddies on the street ..
And it's not out the way both money wise for most households...
A big box of cereal be it cornflakes or coco pops. £3 ish supermarket own brand for 750g enough for a household for atleast 3 days..
Lunch a pot noodle / pot pasta each £1 so say family of 4.. 4x3 £12
Tea.. pile of pasta and some tinned chilli or similar 1.70 a can say 2 cans per day at £2 to feed 2 adults and 2 kids £14 to allow for pasta
Under £30 that's 3 days worth of easy to cook / warm food .. nothing overly inspiring but it'll keep body and soul together