Space disease

Astronauts have lost as much as 60% of muscle and bone mass by extended
stays in space even with exercise. So what would happen if you just let the
body totally adjust to space for several years? No doubt that you could
never return to gravity, but so what. Living in spaced for life is not so
bad. I just wonder what one would finally look like if allowed to totally
adapt naturally to space. There must be some point at which one would
stableize to another form. Perhaps like an octopus with no bones at all, it
would allow for brain growth again.