Uhm.. keep in mind there has only been three people to play Superman since the 1980s, and all three of them struck me as Superman.. but if I had my way, it would still be Mr.Reeve who did have to buff up for the role but was no where as big as Henry. It isn't his body composition though and I'm sure this is the case for a lot of people - sure, naturally some women would dig his chiseled upper body. Anyhow, It's the vibe he projects and his acting ability with the role. It feels like he really is Superman.
And if it makes you feel any better, I'm 6'0", underweight at 135lbs, and a terrible back by way of scoliosis. I don't care nor compare myself to other men, you shouldn't either .