I think it's not the right method.

Instead of attaching your blog posts together into a book, build a book out of ONE blog post that did well.

For you, it'd be a book called "how I lost 25 pounds without trying".

That's what Mark Manson did with the subtle art of not giving a f*ck. The blog post went viral, so he took the core idea and made it into a book.

PS: I ended up reading 54 books this year, which is satisfying. Will likely read 30-40 next year, but they will be longer and harder.