I mean, you can say it isn’t body shaming but it kinda is, and I think you know that a little bit if you feel the need to prematurely defend against it.
In the sense that you seem ignorant of the fact that fat is normal, and can be healthy, The body builds you see, the “super hero physique” of Hollywood, those aren’t the only athletic bodies that exist. (And the Hollywood physique is really not healthy) Real people look like that, and like your comments might be aimed at a cartoon, but shows a belief that likely extends into real life. Most bodybuilders can’t maintain that look all year, and need to put on fat to cut down to muscle, and like starve themselves to make that muscle pop. Maximizing strength means caring about something different than looking at cut as possible. They also tend to lose weight once they aren’t competing and focusing on that strength, but a Viltrumite’s competition would never stop.

But also, Viltrumites had stock designs in the comics. They are clearly taken efforts to diversity the art and standard, and doing that with body types is great. Invincible has always been part commentary on comics, and like this is that kind of stuff. Real strongmen are beefy, and comics tend to be pretty lazy and weird about portraying different body types. Also, he was meant to stand out; he no longer does, as being “the black vermiculite” isn’t unique anymore.