[marginalia_nu]

> My brain is dominated by one set of hormones and nervous impulses right now. Later today - perhaps when I’m more hungry, tired, horny, whatever - those hormones and nervous impulses will change.

This may be true, but it's about as useful as saying our behaviors and moods are controlled by the alignment of the stars. Neurochemistry just isn't something we experience directly, and as a model of phenomenology it isn't particularly informative, this is essentially a corollary of the hard problem of consciousness.

[blowski]

How I interpret your original comment is that you're saying "Jack is Jack is Jack, whether it's Monday morning and Jack is full of energy or Friday afternoon when Jack is tired and hungry. Thus, if Jack wants to lose weight on Monday morning, why would he need help to avoid binge-eating hamburgers on Friday afternoon?".

My answer to that is that Jack's brain is not in the same configuration on Monday morning as on Friday afternoon. Thus, Jack's Monday-morning brain makes a decision to lose weight, and guesses that Friday-afternoon Jack will likely ignore Monday-morning Jack's decision. So Monday-morning Jack also puts in place safeguards to prevent Friday-afternoon Jack deciding to ignore Monday-morning Jack.

Some people do have more willpower, and don't need that help. I'm not one of them, and it sounds like the OP is not either. History is full of self-help advice on this very topic - from Socrates, the Stoics, and Confucius to Jordan Peterson, David Allen, and our very own Paul Graham. So it does seem to be a very real problem.