Sure, you can buy a book. But then it starts getting difficult. You have to read, what is for many here already the utmost torture followed by understanding, which is the biggest challenge in their life.
Having jumped over this hurdle you have to come to your own conclusion concerning your life/style.
And after a few attempts most will fail.
Just use your common sense instead looking for a guide or diet book, which will fill the author's pockets only.