Q: what is slender

A: That's really in the eye of the beholder. The only comment I'd make is that even if your goal is having a slender or even fragile physique, please do not ignore weight training as one of your best allies in getting there! Just because you lift weights does not mean that you'll become bulky and muscular -- by combining a fat-burning diet (which means you're losing weight) with heavy whole-body weight training you'll achieve a slender toned physique.