I believe that most people CAN overcome the addictions.
But, I think the amount of time it takes is different for everyone. One of the things it depends on is how long you have eaten poorly, and what your childhood diet was like.
I did the 100% raw for a while, beginning back in February. I was eating anything raw all day and I was hungry all the time and mentally tortured because of my addiction/withdrawl from cooked foods. After a few months, I found the warrior Diet Forum and decided to eat mostly fruits during the day, but have one cooked meal in the evening. It was difficult for a few weeks, but then it worked really well for me because whatever I wanted to eat during the day, I just saved until the evening and then pretty much ate whatever I wanted then. Then I gradually started eating healthier stuff in the evening. Some days I eat totally raw all day and don't feel deprived.
Don't get me wrong, I still eat "junk food" occasionally. I'll eat ice cream or pizza or white rice or bread, or a fresh french pastry. But actually it's not that often. And after I eat a small amount, I'm either satisfied or sick to my stomach. Sometimes, I plan a "cheat day" and go out to find something yummy and don't find anything I want and wind up going home and eating fruit instead. I think if you do your cheat, then don't feel guilty about it, because that just makes it worse.
One of the keys I think is to be pretty well cleansed and properly nourished because I think that reduces cravings. Some people won't like this, I'm sure, but I think I have less cravings now that I am eating a little more meat than I was before (I was only eating it about once a week, now I eat it about 5 times per week, but usually only in the late afternoon/evening). Usually, I eat raw fish. I even found that raw beef tastes good, like I remember a tender roast tasting. I am not recommending eating raw beef unless it is of exceptional quality; some of the beef here in Japan is sold specifically to be eaten raw. I have also been eating organic yogurt once a week or so. Sometimes I eat cooked meat, like chicken or eggs but not that often.
I think one of the reasons I'm doing well is because I grew up eating a lot of fresh fruits and veggies. I remember eating apples or salads as snacks when I was little and loving it. My husband grew up on a SAD and so when he tries to eat healthily, he has a difficult time because there are very few fruits and vegetables that he enjoys and he grew up on hydrogenated fats and diet sodas and he loves the taste of that stuff, while I have always thought it was disgusting.
I think hopsino is absolutely correct when she says that if you want to eat something unhealthy when you are out, take a look around at the other people eating it and you will probably be so grossed out that you will loose your appetite. This happened to me recently when I was out with my kids at a food court and we were going to get some pizza and there was a VERY large woman with an overweight 2 year old and an obese 5 year old slurping down disgusting food and so we left and ate at home.
Anyway, to sum it all up, I think that the more I cleanse and eat healthy food, the more I want healthy food and not junk. But, when I get stressed out, I still do crave the crap. So, one of the things you need to learn is NOT to stress out about eating (which is actually pretty difficult).
I think it also helped me to search the internet and read gross things about the foods I liked. You can find a lot of info about how animals are tortured or what they are fed or about what Sugar does to your veins and why diabetics sometimes get their feet amputated or why some people think french fries and potato chips contain more carcinogens than cigarettes. Then, think about those articles while you are contemplating eating something crappy.
You are definitely not alone, though. And, I think it's okay to obsess about food for a while. I sure did. Then I started to obsess about why I was obsessing about food. Then, I decided that since I spent over 30 years barely even thinking about what I was stuffing myself with, that it was okay to be obsessive about it for a few months, to make up for the lost time.