Is this universal? (Zero sum-ality of energy for activities)

 I started an intensive language course last month, and my gym attendance really took a big hit.  I describe myself as "chaotically" curious, and am perpetually signing up for (and usually completing) various forms of structured auto-didacticism on sites like Coursera and EDx.

I believe the definition of the term "opportunity cost" is this sense that to do one thing well, comes at the sacrifice of doing another thing.  Picking 'a', means that you no longer have the opportunity to do 'b' well.

There is a real sense of loss when I eventually realize I just can't do all the things that I am curious about.  There is also a need to balance ego-driven pursuits like advanced certification in fields I don't intend to work in, versus outcome-driven pursuits like improving my fitness.  It might feel great and pumped up to walk around with a pro-level Amazon computing certification, but it would be at the expense of my physical and mental-health, and also at the expense of other things I have decided I want to study like languages.

Not to get woo-woo about it, but I have to force myself to believe that being a balanced human being rather than an obsessive, midnight-cramming-session, hunchback computer denizen -- well, is important, and beyond that it's better for the world.  I have written before about how if you look around the room in a group, and all you see is horribly unhealthy bodies and souls, then you should be deeply critical of the work product of said community.

Intermittent fasting as a way to moderate 'boredom eating'...

 One idea I came across somewhere in my travels, is using intermittent fasting as a way to put the kibosh on eating out of boredom at night.   I'm not sure I wholly subscribe to a Jason Fung-ian, or Satchin Panda-ian concept of circadian eating, although what Panda says in particular about "shutting down the highway so the body can make repairs to the road" makes a certain amount of sense. (He is talking about how eating blocks autophagy.)

However, I do recognize that I have a tendency to eat for entertainment, particularly after dinner.  There may be some cases where I am legitimately hungry, especially if I have delayed eating until after noon, or worked out especially hard.  I do think though, that putting a cap in place, closing the kitchen around 8pm, might shave off some otherwise unnecessary calories.  If I get a health boost out of it from a circadian perspective, all the better.