I reckon it's a "eat as much as you can" you nver know when your next meal will be coming along. I'd guess it's either Naval or forces generally. The Navy expression I've seen in many books would relate to just before a major sea battle, they'd all get a hot meal, prior to everything being battened down before Action Stations. The full version of the phrase espec during WW2 was "C'mon lads, big eats, fill yer boots"
Thanks for the reply Chef,I agree that it is probably of military origin?but I wonder if a specific incident coined the phrase,maybe when matelots(lower deck)started to wear boots,as opposed to barefoot in the days of sail?
a bit like our modern doggy bag; 'eat up, fill your boots', i.e. take as much as you can, even fill your boots; somehow makes me think of an open treasure chest filled with doubloons. :-)
Well shiver me timbers....I always thought that it meant when you come across something valuable and in abundance you first of all fill your pockets and then when they are over flowing you start sticking the stuff down your boots. As in pirates finding treasure aboard a ship filled up with the stuff as far as their boots....!
Am I the only one with this impression????