One solution to the rotting food trash situation is to keep it in a box in your freezer. You’ll still have the problem of forgetting to take it out when the trash is collected (until you make a habit of taking it out on time), but it won’t rot. It will take up room, but maybe that could help force you to make that habit of taking it out on time.
The best self-help diet book I’ve read is James Clear’s Atomic Habits. I know it’s not just a diet book, but that is maybe why it is so good. You’ve got to consider your individual habits and routines, what sort of an identity you want to have, and what sort of habits will reinforce that identity.
For most of your other questions, I haven’t read any books with answers, but this recently published one on amazon is selling very well, has good reviews, and sounds like it has some good answers. https://www.amazon.com/Lazy-Genius-Kitchen-Enjoy-Before/dp/0525653945
I think it is worth adding that there is some evidence that not all lithium salts are the same. What this means for obesity is probably unknown.
Lithium orotate is more potent, effective, and less toxic than lithium carbonate in a mouse model of mania (biorxiv.org)