You need a minimum of around 50 lbs of pull to try to kill whitetail deer...
I gotta disagree. My son's Mathews Genesis bow is set to the highest draw weight it has, which is only about 20 lbs, which is comparable to a 35lb recurve in stored energy. It can kill deer. It's all about shot placement.
You see a lot of bows these days for youth and women starting at 30 lbs - they kill stuff too. Very, very few youngsters and women could ever pull the 50lb minimum you speak of - so I have to take issue with that statement.
I pull 54#. If my bow were set to it's max 60# draw weight, I would only get about 2fps more and at what cost? A shoulder or two. Maybe an elbow.