i have a question... about actor weight

ok so i started to look in to this show and i remembered Nishant Singh from Jub Miley Hum Tum and he being slim its hasnt't been that long and i saw he was in other shows with fit bodybut i did read he had to lose some weight for another show. what i want to know is was he asked to put on weight? i mean he is playing a character in his 40+ or so but still i get distracted so much he looks so huge specially since hes so tall if he wasn't so tall i think it would have been avoidable. i tried to google and couldn't anything so thought i should ask everyone here thats always up-to-date :P