As the title asks, what is the difference in usage between пи́ща and еда? Is one just a more formal version of the other? Are there any people/situations to which you could not usually apply one or the other?
The aspects of difference:
Пища из more formal version of еда in the meaning 'food'.
Unlike пища, еда can be used directly in the meaning 'having meals'. e. g.:
- (разговаривать) во время еды
The formal (medical, dietological) version of "еда" here would be "приём пищи" ("во время приёма пищи"), not simply "пища".
Unlike "еда", "пища" can be used idiomatically (пища для размышлений, пища для ума, пища для сплетен).
Пища is a more abstract word than еда and is related to what people or species living somewhere eat typically (пища панд - бамбук), not in a current situation (еда у путников /или у их собаки/ закончилась).
Adjectives, derived from the two words, have different meanings. Пища -> пищевой (intended for usage as food ingredient, permitted to have contact with food - about a material, etc. somehow related to food). Еда -> съедобный (=edible; idiomatically, having fair taste).
Еда is more colloquial than
пища, and is generally only used to refer to the stuff eaten by humans. If talking about e.g. dog/cat/cattle food, one should use
еда is more of a generalized concept of edibles than a pointer to something specific. If, for instance, you'd like to say, 'Let's go grab some food', the correct phrase would run along the lines of "Давай купим что-нибудь поесть/съестное", not "Давай купим еду". The phrase 'I like this food' would translate to something like "Мне нравится это блюдо", or probably lack a direct reference at all: "Мне очень вкусно/понравилось". "Chinese food" would be "китайская кухня" (cuisine), etc.
Technically, of course, one can say, e.g., "Мне нравится эта еда", but it will sound somewhat childish and not 'well-bred'.
еда may refer to the process of eating, as in "Во время еды не разговаривай" or "Мы потратили полчаса на еду". This is probably the most commonly encountered usage of the word.
Пища, on the other hand, is more formal, but, much like
еда, is used as a general concept, not denoting anything in particular. As noted by AlexVB, you'll find the word in all kinds of metaphorical and allegorical idioms as well.
I would say that пища is not just more formal, but also that its usage is limited to written language.
But there are several widely used expressions with the word (and you cannot use еда here):
- пища для ума/размышлений - a problem worthy of consideration - "food for thought"
- духовная пища - something feeding your spiritual development
A more common word for food, which can be used both in formal and informal contexts, is продукты [питания] (always in plural).
1.At first, both пища & еда seem to be interchangeable, but this is a wrong assomption, since they are [almost] interchangeable only in phrases like
Я даю животным пищу. [sounds not quite natural]
Я даю животным еду. [sounds ok]
Я даю детям еду. [sounds ok]
Я даю детям пищу. [sounds ok]
2.Stylistically пища is more official, neutral, conservative and distant than еда, especially in coined expressions;
Сейчас в больнице время приёма пищи*. (one never would say * ***Сейчас в больнице время приёма еды* ).
Будет день, будет и пища (never * Будет день, будет и еда).
Аппетит приходит во время еды (one would never say * Аппетит приходит во время пищи, because the overall tone of the saying is close / friendly, non-distant).
3.Morphologically (and semantically), пища is more likely to comprise the act of cooking / modifying a food, or, to put it in other words, пища is more about a prepared food whilst еда is more about an action (from an eater's point of view);
Книга о вкусной и здоровой пище (and never * Книга о вкусной и здоровой еде) - a title for classical Soviet cooking guide from the 1950s.
За едой мы (не) разговариваем (hardly * За пищей мы (не) разговариваем).
4.Cognitively, as the action names, пища refers to an indefinate / non-evidential action, whilst еда is more likely to signify a definate and evidential event.
Это - на еду / для еды (saying * Это - на пищу / Для пищи is improbable).
Я уже заказал еду (and definately not * Я уже заказал пищу, not even in official context).
5.Mind the words питание and блюдо as well.