That's a nice theory, but I'm going to call [citation needed] anyway. Can you cite any explanations of how weightlessness would cause something like cataracts or insulin resistance, or even of whether there's a statistically significant correlation focusing on the single variable of weightlessness vs. others that might be involved?
The symptoms match health effects caused by a sedentary lifestyle: https://en.wikipedia.org/wiki/Sedentary_lifestyle#Health_eff... . In a gravitational environment, just moving around is a form of exercise since one has to move about the entire weight of one's body. In space, where everything is weightless, it takes much less effort to move around and you see the same effects (even with rigorous exercise routines). Imagine exercising for an hour or two and then sitting down for the other 22 hours. You'd end up with similar health effects.
The authors found a "convincing" correlation between sedentary behavior and health risks only for for cancer and CVD (see the "discussion" section). They specifically looked for such a correlation to insulin resistance, but didn't find any; they didn't look for other symptoms that have been mentioned (e.g. cataracts) at all.
It's not at all clear that weightlessness is the same as sitting at a desk in terms of the conditions we're talking about, but there is evidence that their rigorous exercise programs should counteract any such effects anyway. I'm not saying your theory is invalid, but you've done anything but provide evidence for it. It's certainly not the kind of "slam dunk" that would have justified your haughty dismissal of the OP.
