this "common knowledge" "weight loss" stuff typically neglects how dieting will affect ur caloric rate. if u just starve urself, ur muscles will grow smaller and u will need fewer calories to maintain ur normal functioning body, meaning u need to eat even less again to not put on fat. but if u train ur muscles directly, they will beg for more calories so they can grow, and the calories needed to maintain them will also increase.

for anyone interested, i suggest reading a physical education by casey johnston.