That's a bit excessive. I did a ride of 3 hours on the weekend and put 1832kJ worth of energy into the pedals, that translates (at 25% efficiency) to 1750kcal total energy expended.

It's actually pretty difficult to eat back those 1750kcal if you don't go out of your way to stuff your face with sweets.

The point most people (and certainly the press) misses with the "exercise doesn't work!11" meme is that of course it will never work if you simply see it as some kind of tool for weight loss or necessary evil. You are just going to stop the moment you have your "goal weight". The point is to turn the exercise (rather, find a sport) into a habit, a hobby.