This article is from the Diet FAQ, by Claudia McCreary firstname.lastname@example.org with numerous contributions by others.
Your weight is only a very rough indicator of the amount of fat that your
body contains, and most physicians feel that the percentage of your weight
that comes from fat tissue is far more important than total body weight
(which includes not only fat but also muscles, bones, and bodily fluids).
Height/weight tables could indicate that a lean, muscular person is
"overweight", while a person whose weight is within the "normal" range might
actually be carrying around more fatty tissue than is healthy. Covert Bailey
states in The New Fit or Fat that standard weight tables can be off by as
much as 20-30 pounds for any given person.