Interesting. So let's say you wanted to minimise your risks of CHD as the OP mentioned - you would just go here and find out the highest correlates and trust them enough to base your whole gamble on?

I totally agree with you that the reference class problem is a real problem, but having access to a process for quickly finding accurate base rates is still a problem.

Do you have any data on how long the conversion takes?

What time did you take it? D3 is a strong cellular modulator of our clock genes https://www.vitamindcouncil.org/new-research-finds-activated-vitamin-d-regulates-genes-involved-in-the-circadian-rhythm/

Interestingly, this fits with what Paul Graham replied to my email (about career advice) a while back:

I would choose whichever you find most interesting.
It's more important that you be excited about what
you're doing than which particular field you're working in.
Just ask yourself what would be cool, in an ambitious
way, to know more about.  --pg