I've experienced a bit of everything, talking group-wise, not food-in-play- wise.
I've had, what I think its the most common, everyone just brings whatever they want for snacks. This usually involves "junk food", chips, pretzels, the all-mighty Doritos, various candies. Generally speaking, I only ever played with friends, so pretty much anything was available for anyone to pick at. Every now and then you get someone who is "wonky" about sharing their food (OCD folks or whatever we'd cvall them nowadays).
In such groups (for me, mostly during the high school years), if we were in for a marathon session (an "all-dayer" or "all-nighter"), ordering pizzas or the like was not uncommon.
In college, the group was smaller (and obviously poorer) so "eating in" was more common. Snacks still appeared sometimes, but we got into a lovely ritual of a "dinner break" in which someone would cook for us. We get away from the table. Get to discuss what's been happening in game, what we want to do when we resume play, and perhaps most importantly socialize about stuff NOT in-game. This helped us all be more focused and game-oriented when the meal was done and the game resumed.
Around holiday times, it is not uncommon for there to be prepared foods or a "pot luck" thing for us all to eat and enjoy everyone's specialties.
AND, I had a DM who was an excellent baker (at the risk of boasting, I am an excellent cook, but baking not so much. I'm not really great with desserts.). She would occasionally, for some special occasion or for sometimes as an "in-game" prop (some special treat we found in the village we were in at the time or some magical cookie sitting on a table...for the latter, it had to be tried/tested in game by someone before we were all allowed to "dig in" without game consequences). Might be some homemade specialty, could be as simple as a roll of Pillsbury slice'n'bake cookie dough. Either it was still fun and appreciated by the group.
I always really enjoyed that...having real food props for game-food elements. It's amazing how it helps the immersion when you engage those extra senses (taste and smell). I don't really do it as often as I should but always thoroughly enjoyed it when I encountered it in other groups.
As for in-game/PC eating, I do both. Never much for book-keeping, but much for "realism", everyone did have to eat, at least once a day.
In a wilderness situation its usually a hand-waved "mark off your iron rations" before they broke camp or bedded down. Sometimes a ranger or other PCs might want to go hunting while the rest of the group sets up camp. I'm happy to role-play those moments and roll some dice to determine their success or lack thereof.
When they are in civilization the characters eat more, obviously. They typically get (assuming they can afford it) some real/hot breakfast (even if it's just porridge or bacon and eggs), a dinner that involves cooked meat along with staples of the region (breads, fruits, cheeses), that kind of thing. Whether it's ordering at the inn/tavern/pub, a feast at court or a festival going on in the town, there's just more opportunity for the characters to sample the local cuisine...and, for most players, having their characters who spend so much time away from civilization eating iron rations, they are happy to do so and seem to enjoy the options I offer them.
In those instances (probably because I am an avid cook) I try to describe at least a few of the foodstuffs available and describe things in as much detail as possible so the player (hopefully) gets a real sense of what they're eating...and thus a "realistic taste" of the region they are in.
Just as a note on that last point, never forget that people (even common folk) like to eat good food. Saying "they bring you a half of roasted chicken."...while good is not as good as "they bring you a plate of half a roast chicken stuffed with apple, sage and rosemary smothered in a thick brown gravy that smells of garlic and herbs." IOW, when describing the food of a region, always take into account the available herbs and spices that are common/available to the area....is the local cuisine "bland" or do the residents enjoy "hot/spicy" flavors, do they use "tomatoes in everything" or pride themselves on the local wines, etc.
Also take into account that all cooks are not created equal. The cheaper inn in town might bring you a chicken that is tough and overcooked...the skin is burned...etc. It's still edible! Still better than a self-prepared grouse on a spit over a campfire in the woods...But not as enjoyable as if you'd spent the few extra coppers to get the same meal at the pricier inn down the street.
Have fun and happy eating. (and good luck with the new group!
--Steel Dragons
