On the other hand, James Harden seems to lose a fair enough of weight.
Take a look at this photo:

Isn't it good

Well, of course, such sudden changes of James Harden draws out different side of judgments.
If James Harden was averaging 36 and cooking the whole league while looking like this... slim Harden is about to be the GOAT
I don't know that Harden losing weight is necessarily a good thing. One of the main reasons he is so lethal going to the basket is his size, and based on the minutes he's been able to handle in the past, I don't think stamina was an issue
IMHO, it is good. Though significant amount of weight helps him to force his way in to the basket but we couldn't deny as well that there were some slim players who can do what he does like Manu. And I think, his new shape might boost his agility, and balance.
Source:
https://www.google.com/amp/s/heavy.com/sports/2020/05/houston-rockets-james-harden-weight-loss-training-look-see/amp/