Just wondering why its suggested that for people trying to lose weight they should also do some weights..? I don't really know much about weight loss, maybe its not suggested, but I read alot of peoples posts here and they all seem to have some form of muscle building.. maybe someone can explain to me

Mainly to keep what muscles they already do have from shrinking and getting weaker, which is atrophy. But, it does burn calories and boosts your metabolism as well, plus even if you can't bulk up, you do in fact get stronger. I dieted all winter, lost nearly 20 pounds, and during that time I went from barely being able to do 20 pushups and being sore for 3 days, to doing 120 a day.

Not so much muscle building so much as muscle preserving. When you lose weight, its all too easy to lose lean body mass as well as body fat. We want to lose weight and to improve our fitness, right? Well, its a good idea to incorporate some resistance training into your exercise programme in order to achieve this.