Disclaimer: Of course you are beautiful and perfect at whatever weight you happen to be.

-You say "Ugh, my jeans are tight! I've been eating too much lately!"

-He really hasn't noticed

-He looks surprised and suggests that if you feel uncomfortable maybe you'd like to come to the gym and train with Bisky 

-He says she will whip your butt into shape fast

-Killua probably does notice when you gain a little weight

-It doesn't bother him, just saying he can tell, because he's detail-oriented

-He calls his brother "Piggy" so he is aware of weight issues

-He mostly doesn't like that it makes you crabby

-Hides his chocolate candy so you won't be tempted

-He's always working and preoccupied so he seriously has no clue 

-Says "What? Your pants don't fit? Huh?"

-You'd have to gain a literal ton of weight to make any impression on him whatsoever

-Notices

-He's a medical student so helpfully offers up a doctor-approved diet plan which makes sure you get all your nutrients while still being able to cut calories

-Notices

-Likes it

-He's into cuuuuurves in a porno way

-Doesn't notice

-Doesn't care

-This sort of stuff does not register at all

-He has an obese brother and that goes over his head too

-If you try to discuss, it he will ignore you or stare at you blankly

-Notices

-Like Hisoka, he thinks it's kind of hot

-Buys you some new clothes that show off your bigger ass 

-Doesn't notice

-Really does not have time for this shit

-If you feel fat then go work out

-If you don't want to do that, then why are you wasting his time, what do you expect him to do about it

-Notices

-Is very sweet about it

-Says you are attractive no matter what

-Suggests long walks and other forms of pleasant exercise