It's not about weight, it's about fitness, and one component of being fit is to have relatively low body fat, because fat is not very efficient, whereas muscle is.

Deborah Bull CBE (born 22 March 1963) is an English dancer writer and broadcaster and Creative Director of the Royal Opera House. Born in Derby and brought up in Kent and Lincolnshire Deborah Bull studied dance from the age of seven first locally and then on the recommendation of her teacher at the Royal Ballet School.