The best advice I can give for someone that has been doing this for more then a decade, the fastest and best results will come from 100m sprints, starting with 4 then all the way to 12, 3x a week.
I have done everything from boxing, muay thai, weight lifting etc. nothing comes even close to sprint workouts, my whole physique changed as a result very rapidly as did everything else, nothing strips off fat quicker and builds lean muscles faster then this.
Just take a look at all sprinters from professional/amateur ranks then compare them to those that do weights or other sports, it's a no brainer!.