Go ahead and eat one. Maple bars are so fucking delicious. Just don't google the nutrition information for it later.
Turns out a maple bar is 470 calories, ~60% from fat. That's bad. (This is the kind without jelly/custard filling, for those keeping score. That adds another ~200 calories.) That's roughly a fourth of the average person's caloric intake for a day.
On the other hand, I guess that means you could just eat 4 maple bars over the course of a day to get all the calories you need. That's kind of rad. You ever have those days where you wake up and you're like 'I want to do something destructive to my body today, live life on the edge and feel alive'? I suppose 4 maple bars is better than a pack of cigarettes. It may not be as popular as the stereotypical mid-life crisis where you go buy a motorcycle/sports car, but it's so much more delicious.