We can't just see if the fats he burned were turned into muscle since he has his jacket and shirt on. But either way, I think it's good, he'll be more quicker, and he doesn't need to rely on his weight to attack the rim with his low post skills anymore, and lastly it won't be as tiring as it was carrying his body weight. Beside it doesn't change the fact that he still has his skills on passing  .

Take a look at KD, despite his skinny body shape he dominate guys that even twice to his body weight, the body he has helps him a lot from jumping upto attacking the rim way quick more than the other guys the same or as close to the height as he has. And I think, it will be also a great help to Jokic although the two man have different playstyles but that additional speed he would acquire is  important, IMO  . He just need to develop muscle and increase his strength from now on.