Intermittent fasting did not work for me .... but it works really well for others. I am always willing to experiment when I am not getting the results I want anyway.
As for "Coming back," I haven't had any serious injuries---a broken collarbone, but that wasn't that big a deal .... it was a mix of mental and physical issues interacting which dropped my riding from several thousand miles a year to a few hundred.
Now that I am getting back into riding, I find that all my old "goals": farther, faster, more! are meaningless. I feel pretty wiped out after short slow rides, which is okay, but it seems increasing performance is glacial---it is really hard to stay consistent and even if I get several riders in a row, every one is slow and difficult. I am doing a little better than five mph, but not hugely.
For me, the only thing that matters is reconnecting with the joy of riding. I cannot ride for speed, or endurance, i cannot go exploring new areas---I cannot even ride to the end of the areas I already know. The only thing I can do is Ride my Bike .... and it turns out, I still like riding my bike.
I still track my numbers, but I really don't mind if they go up or down. That is no longer the point. If I can get out away from the desk or couch and ride at all, I win.
So, ride short, ride slow, ride without measuring anything, whatever. If you like riding, ride your bike. it is the thing in itself.