We're considering the extent to which starships in specific, and space travelers in general, are able to stock their larder before departure. By mass considerations alone there stood no mathematical objection, a five year supply of food and water (even if unfiltered) for 430 people does mass less than the ship herself. But it's not only the mass, besides that there's also the volume such stores require. Given clever packaging there's every reason to think such stores could be consumed releasing new living space, akin to contemporary ant farms with tunnels literally eaten out of a nutritious, non-toxic gel. Sorry for any unmerited comparison.

Last column calculated some 500mt of food and over 2200mt of water are required to "prestock" the entire five year mission. The volume of the water is simple enough, since at one kg of H20 per liter that much water would require a cube-shaped tank about 13m on a side. Clearly that amount would fit with ease within a heavy cruiser having more than 160000m3 internal space, though once again it is noted this represents potable water for drinking only, none for hygiene or cooking.

Food is more problematic, what is the density of "food?" From online sources it seems almost all "vegetable" foodstuffs from grains to fruits to nuts are less dense than water, while meats (the real stuff, not rikerburgers) are about one quarter more dense than water without bones and over twice as much with (toted all the way so the crew can throw them away? There's an unlikely luxury!). This yields a reasonable estimate for average "food density" (that includes packing materials) at twice that of water, say 2000kg/m3. The five year mission entire food supply could be stowed in just over 1000m3, a variegated crouton slightly larger than 10m on a side.

Altogether the provisions for the mission come to about 3250m3, about 2% of the ship's internal volume. (That seems a little less than what the ant tunnels expose but that's just a visual guess. And of course the ants aren't supposed to live there for five years!) I estimate water for non-consumption uses would require another three or four times that amount, nearing an uncomfortable ratio of 10% of total crewspace, but filtration systems would undoubtedly reclaim some of that. Having established these figures we're left with a riddle from "Charlie X": Why it would be difficult for Enterprise to carry "real turkeys" even if the crew was to eat Thanksgiving dinners three meals a day for five years?