In order to lose body fat, build big strength gains, and simply be as functionally able as your body was meant to be in...you have to do compound movements. As in multi-joint movements. Get as many muscles moving at the same time as possible. It promotes natural growth hormone (to help muscles and other tissues recover and grow stronger), and "trains" your muscles to work in synch which makes you stronger and more efficient. And, more muscles moving means more calories burned: fat loss!
Does it have to be as crazy as what you're looking at in the picture below? Nope. Work at YOUR level. But get lots of muscles moving simultaneously. Your body will love you for it.
Jesse
212Workout.com