The Easy Way to Lose Weight (Allen Carr's Easyway) is a great start. It works to change your mindset around food, how diets don't tend to work long term, but how to adjust your relationship with food for long term results. I found it incredibly helpful, and although i didn't follow it to the letter (for example i wouldn't ever stop eating meat), i took what i wanted from it and made some changes and found it successful. It speaks about becoming in tune with your hunger signals, what food is going to satisfy you, and also allows for 'junk' here and there. Its not a diet, but really addresses people's unhealthy relationship with food, whether that is overeating, not eating enough, and junk food/cravings.