[LisaS]

re: leanness - you have to be stronger to pull up a heavier person.
- e.g. let us say you have the muscle to pull up a 150 lb person. If you weigh 233 you aren't going to be successful. If you have the muscle to pull up a 100 lb person and weigh 130 lbs you won't be successful either but you are closer to being able to do it even though you are weaker at an absolute strength level.

So you work on getting stronger (and weighing less if needed) and at some point the two lines will cross and you'll be doing unassisted pullups at whatever body weight you are. Then you'll start holding dumbbells between your feet to make yourself heavier. Ironic isn't it.