the first apple sails by missing him by an inch, as he ducks his head and weaves through the barricaded furniture by the front fate. A second apple whizzes by and hits that nasty postman who explodes in a cloud of letters. Target in sight, he bounds up the stairs and into the first room on the left and delivers his cargo by masters feet: a fresh basket of apples. He's a good boy.
Eating "anywhere from 150 to several thousand" apple cores will kill an adult with cyanosis so... maybe stop worrying about how many you need to eat and start figuring out how to feed them to people.
I don't know about apples, but if you just want people to stay away, then, according to anecdotes from others (definitely not personal experience! Stop looking at me), the following will keep you on the throne:
2.5kg of oranges (2.5kg with the peel, if you eat the peel you may be able to reduce the amount IDK). Ingest the oranges over the course of an afternoon, where you're bored out of your skull watching the same long play VHS-tape.
1kg of assorted wine gum and foam. Ingested over the course of an all nighter at a LAN party.
750g of peanuts. Ingested in the back of the car, while your parents are becoming more and more desperate, trying to navigate out of Liege, for 2 hours, in the time before smartphones and car GPS. Careful with this one, most Citroëns don't a toilet build into the back seats.
ANY amount of the pinkish sweet middle part of the 20cm tall pine cones that grows directly into the air. Just don't be a retard like yours truly on this one.
Since this specifies how many to eat, probably only like 10. That's a little over the daily value of fiber and since most people don't usually eat as much fiber as they should anyway, that should be enough to get some pretty good gas happening.