Over on the Reactions YouTube channel, they worked out a formula that gives you an estimate for how many lollies it'd take to kill you. The video uses a lethal dose formula called LD50, which in this case equals the toxicity for things consumed all at once. This doesn't necessary guarantee death, it's just an approximation that would likely kill about half the population. Of course, they also can't kill humans to verify this, so it's a rough estimate based on studies in rats. Either way, to figure out about how many sweets you'd need to eat to kill you, just substitute your weight in for W (in pounds, in this case, so you'll have to do a bit of unit conversion) in the equation:
(W*13.5)/9.3 = PIECES OF FUN SIZED CANDY
(W*13.5)/1.5 = PIECES OF CANDY CORN
It's likely an insanely large number that most of us will never actually get close to eating in a single sitting, which is why it's probably safe to let your kids eat all the lollies they want.
How Much Candy Would Kill You? [YouTube]