I realise there's a lot of this lately, and I'm about to add to it, but here goes:
A perfectly valid question. The single answer given is a start, as is my comment, but put together they are still insufficient and unreferenced. (The poster admits this: "I've answered below with the only meaningful distinction I can think of.") Question closed, as exact duplicate. The "exact duplicate" thread has no mention of lunch in the question, but it's sort of about food-type things. Fine. There is one single answer: it is, equally, a start, but insufficient to entirely answer the question at hand; and it does indeed mention lunch, but only to state that "do lunch", "have lunch" and "eat lunch" are all English phrases. The best advice given is "just learn them one by one" - but nothing is said about their differences.
The most frustrating thing about this is not that none of the five closevoters spent the 10 seconds necessary to realise that the threads were not duplicates and their single answers were insufficient for either question, but that one of those closevoters was also the author of both of these answers. Words fail me.
Please reopen this thread.