I've recently become an iPad convert. One of the apps I installed almost as soon as I got the Pad was The Recipe Box, which allows users to store all their recipes. I've been transferring pretty much everything (I love cooking; good job I'm a fast typist) over to the Box.
Like most of us, when I'm doing something dull and repetitive, I crave distraction. I had the Escapist's most recent podcast on, and as it happens they're almost as obsessed with food as I am. Which is to say, about half as obsessed as the folks over at YSDC; the Bradford Players' audio games are liberally mixed with food references (about 2 tablespoons food to 1 cup game, I find), and they're particularly fond of hampers. Thus as I typed my mind turned to thoughts of food and gaming, particularly RPGs.
Food rarely appears in game, except for the occasional quick reference. I find this odd. In RPGs particularly, the Keeper often needs to create a mental image, or a sense of foreign climes, and the senses, including taste, are inextricably linked to memory. Sweet, sour, bitter, salty, umami, all evoke certain memories or reactions, and there are kinds of cuisine that automatically signal particular associations in our minds. Moreover history shows us that the search for food has changed our world. When Columbus went looking for the Indies, one of the things he was after was spices; Spain wasn't happy paying the high Venetian tariff for access to saffron and cardamom. When he accidentally came up with tomatoes, potatoes and corn he changed European cooking forever. It's almost impossible to imagine what Italian cuisine, for example, was like without the tomato, or what the English roast would be like without potatoes. Ireland's history would be very different were it not for the Famine, and there are hundreds of other examples of food gone wrong that had terrifying consequences. There ought to be all kinds of stories to be told about food, but we don't seem to tell them that often.
In game, I tend to set up a shortlist of locations and NPCs that I know the protagonists will encounter at some point. For instance, no matter what the setting, it's a pretty good bet that the characters will meet law enforcement officials at some point, or criminals, or innkeepers. That's just the nature of the beast; characters commit (or avenge) crimes, occasionally work for crime lords or the authorities, and always need a place to lay their weary heads. That's true almost regardless of setting, and in some cases the setting only reinforces the truism. Ars Magica had its mighty wizards deviously plotting their advancement, possibly even assassinating their rivals, but everyone wanted to stay on the good side of the Guernicus, and the sensible Storyteller always had a couple of them on hand for those moments when power-mad players started getting above themselves. Cyberpunk 2020 wasn't big on law enforcement, but crime ran rampant and more often than not it was the players who were up to their neck in the mud. Bond wouldn't be Bond without his encyclopedic knowledge of Chateau Lafitte. So on and on, and to that list of 'NPCs I know I'll use' can be added the Restaurant/Bar.
As Keeper, you know full well the characters are going to want to eat at some point. You also know that there are plot points that can be reinforced by eating. In Cthulhu gaming, the most popular plot point is cannibalism, and there are groups within the setting whose entire culture is defined by their dietary needs. Even without this direct plot link, there are going to be times when you as Keeper want to reinforce the nature of the setting by referring to the characters' surroundings. Or to put it another way, the characters have a different expectation of standards aboard the Orient Express than they do of the Stumbling Tiger Bar, Shanghai. Food is an excellent way to reinforce the nature of the setting. There's no reason why you shouldn't dwell on the excellence of the cuisine (or even borrow some inspiration from alternative sources). Alternatively the Keeper could focus on the liquid side of life, though I suppose it's not impossible that the Stumbling Tiger laces its brew with formaldehyde.
In each case I'd recommend simplicity. With any commonly encountered NPC type or situation, you shouldn't need more than one index card's worth of data. As this is information that isn't linked to a particular scenario, this is a mini database you can build whenever you have a free moment. Half a dozen restaurants, each with a shortlist of House Specials, or the same number of bars, each with its own peculiar cocktails or brews. That's enough for everyday use, and then they can be dropped into the game whenever you see fit. If you know you're going to be running a particular campaign, then plan tailored restaurants and bars to suit the setting. You don't have to know exactly what a fillet of beef pickled with juniper and coriander, served in a red wine sauce, tastes like, but you do have to be ready to use that menu information on the players so that they know they're on the Orient Express, not some trunk service to Brighton.
Point being, in an RPG the players need to feel as though they're playing roles, getting into character. For that to happen they need to have a clear sense of identity, and the senses are part of that identity. Food and drink helps reinforce identity, by giving a clear, unambigious message straight to the brain. 'This tastes good.' 'This reminds me of home.' 'Ugh! Funny stuff these foreigners eat.' 'Mmm . . . spicy!' Anything you, as Keeper, can do to reinforce the players' sense of identity ought to be done, since this can only help the game progress.
Of course, if their first reaction is 'dammit, now you've made me hungry. Let's order a pizza!' you'll know you've done your job properly!