Thanks Dimitra, but why wouldn't you say so? Here's how wikipedia defines staple food: "A staple food, or simply a staple, is a food that is eaten routinely and in such quantities that it constitutes a dominant portion of a standard diet for a given people, [...]" (https://en.wikipedia.org/wiki/Staple_food). Isn't that also the meaning of βασικό φαγητό?
Yes, that's indeed how wiki defines it. Well, this is just my personal opinion, but a staple food (as Wiki also mentions) is usually something inexpensive. A basic food in someone's diet might not be a staple in that sense. I just think that staple is a bit too specific in this case, considering that food here doesn't necessarily mean τροφή (which is what would actually be described as staple.).
But again, this is just me. :P