This is one of those things that you learn about, and then you notice it all the time. It first came to our attention when we saw a British police series episode where the office goes into her superior’s office and sees grapes on the desk. Her immediate question was, “Grapes? Who’s in hospital?”
That’s very specific!
It was strange. On the ground floor of the hospital they actually housed a police facility. There was drama involving women who gave birth, then multiple men claiming they were the father would show up to visit. Fights erupted and police responded.
The first thing that came to my mind!! 
Well, I’m always thankful to have a little chocolate in the hospital as a distraction from the bland hospital food. Little quantities don’t do damage, and it’s good for your mental well-being, chocolate makes happy.
What’s unhealthy about chocolate? Alcohol I get, but I can’t see it as being any worse than grapes, which are all sugar practically.
You know I can’t eat hard-boiled eggs and nuts.
You sir have won the thread with this.
Well, it’s basically just sugar and fat, and for some people with already bad eating habits too much chocolate isn’t a good thing, but I also don’t see how for a non-overweight person who’s not on a special diet, chocolate in moderation might be unhealthy.
Sure, but how much chocolate does one eat at a sitting? Not a hell of a whole lot. Or at least not me. I’d probably eat more in sugar of the grapes than I would of the chocolate.
Plus, chocolate is actually recommended if the reason you’re in hospital is because you’re recovering from a dementor attack.
Another trope/meme/stereotype/cliche is that the visitors who bring
the grapes/chocolate/whatever will probably eat most of it !
Never heard of this before! Thinking it’s a brilliant idea, though and will, from now on, def take grapes to people in hospital.
Also, if I’m in hospital, please DO bring me grapes. I love grapes and will be delighted, I promise.
Just asked my gf and she never heard of it. She initially thought I was joking, I had to show her online mention of it.
I learned that from David Lodge’s Therapy.
Grapes because you can spit the seeds into a bedpan.
I eat lots of grapes, but haven’t had one with seeds in decades.
No chocolate because the nurses will undoubtedly confiscate it. What happens to it later is anyone’s guess… 
I do. I love the big fat juicy red ones, seeds and all if the seeds are soft/small enough. If they’re too conspicuous I’ll switch to seeded red ones.
I first found references of bringing grapes in the Rivers of London series. So if it’s a cliché, it’s a current cliché.
I have no idea how recent it is, but it certainly pops up in current TV shows.
And I understand why grapes might be a good gift to bring to someone in the hospital (compact, sweet, no peels or seeds, etc.), but it seems to me that this goes beyond the practical aspect to the “strong association” of one with the other. I wouldn’t call it an established tradition, but it is certainly close based on what I see and read. When a person sees you have grapes and immediately assumes someone is in the hospital, that’s pretty compelling.