Most Helpful Girl
I do sometimes, if a book is really interesting, but usually I try to slow down so I can better absorb what I'm reading. It depends on the subject too: how difficult it is to understand, how important it is for me to comprehend everything, the style of writing, etc. I can be pretty analytical in the way I read, and for research papers and essays, it actually saves me time in the long run. It's also not uncommon for me to go back and re-read a passage to figure out the minor nuances, or appreciate the way something was phrased. I find it more enjoyable that way, to stop and think about things a little, instead of speeding through it.
However, if you want to read that fast, practice helps. The more reading you do the faster you get, and if you're interested in the material--that helps too. I also think I read faster if there's no one around and I'm completely focused. This article has some good tips if you're interested: link
Speed reading is a useful skill, but I think it's better if you can read fast and comprehend everything to the extent you want to, which might take some training.