In the last Brisingr-spork chapter we briefly discussed the oddness of the food in Glumra's home, and how the dwarves in Farthen Dur would keep supplied with eggs, and that got me thinking about the whole problem of how a dwarf community that lives inside a mountain - as dwarves traditionally do; that's certainly canon - could plausibly supply itself with food. And it seems to me a question that doesn't get answered by many authors.
AFAIK Tolkien, whose dwarves eat just the same food as men and hobbits do, addressed the problem just once: right at the beginning of The Hobbit he has Thorin say of the kingdom of Erebor that in its heyday, when jewels and metalwork from Erebor were in Middle-earth-wide demand, "Fathers would beg us to take their sons as apprentices, and pay us handsomely, especially in food-supplies, which we never bothered to grow or find for ourselves." OK, yes, that would work.
It's at least a functional economic strategy, although a high-risk one: a war or plague or trade embargo anywhere at all along the trade route to the south could disrupt the flow of food imports and leave you suddenly starving. But Tolkien never explains, for example, how Balin's people supplied themselves when they re-took Moria, when they weren't in routine contact with anyone else as far as I know.
Have any other fantasy authors produced any explanations of how a subterranean dwarven culture keeps itself supplied with animal and vegetable food that can pretty much only be sourced above ground? Or, indeed, why it should choose to live on that kind of food anyway?
It's such a traditional trope - which Tolkien among others subscribed to - that Dwarves 'grow out of stone' or were 'made out of stone', that you'd think one obvious answer would be that as a silicon life form they actually eat minerals, not meat & veg. But I don't know any authors who subscribe to this theory. If there are any, I'm pretty sure it's here that I'll be told about them!