If you're the type to read "diet books", then you might take a look at Making Weight Control Second Nature by Susan Burke March, MS, RD, LD/N, CDE. (Disclaimer, Susan is a colleague and a friend.)
Susan makes an interesting point in the introduction to the book: She is very lean and people presume that she has been that way her whole life. She mentions that she was once 40 pounds heavier (wouldn't I love to only be 40 pounds overweight!)yet people presume that she is "naturally thin". Susan doesn't think anyone is "naturally thin" but that everyone who is thin works at it. Maybe some people don't have to work at it as hard as other but even people who've never been fat, don't gorge themselves on hot fudge sundaes and fried chicken every day.
I do agree with her. We've all seen a slender person eat a huge meal and that's what makes us think, "She's naturally thin. She can eat whatever she wants." Well, she can't eat whatever she wants and she doesn't eat whatever she wants all the time. That's the point. "Naturally thin" people, those who are lean and maintain their leanness throughout life, are probably much more mindful eaters than those of us whose weight fluctuates between fat and very fat.
Think about it. We base our belief that someone is naturally thin and can eat whatever she wants on occasional observations of the person stuffing her face. But what about how that person eats every day? Every month? I have no scientific evidence to back this up but I'm confident in my presumption that "naturally thin" people don't eat the way I do.
Take a look at Susan's book.