Green’s Dictionary of Slang

packing n.

[SE pack, i.e. the stomach]

food, esp. of poor quality.

[UK]J. Bent Criminal Life 272: Packing ... Food.
[UK]J. Ware Passing Eng. of the Victorian Era 191/2: Packing (Peoples’). Food.
[UK](con. WWI) Fraser & Gibbons Soldier and Sailor Words 219: Packing: Rations. Food in general.

In compounds

packing-house (n.) (also packing-ken)

an eating house, a café; thus packing house quail, spare ribs; packing-house rules, no rules at all.

[US]L.A. Times 9 Apr. 5: ‘Packing-house quail’ – spare ribs.
[UK]J. Ware Passing Eng. of the Victorian Era 191/2: Packing (Peoples’). Food. [Ibid.] Packing-ken (Low. Class) Eating-house – because you pack the food in your stomach then and there.
[US]Van Loan ‘The Redemption Handicap’ in Old Man Curry 187: From now till the end of the meeting it’s packing-house rules, and everything goes.