janewhite1 has some wonderful suggestions. Listen to the wise jane.
Here are a couple of thoughts from me:
If you're looking for some structure in learning about good nutrition, you might check out the DASH Diet, which you can find in a book at your library or bookstore or online at the government NIH website
No, you don't have to restrict yurself to eating salads. By learning about healthy food groups, you can learn to incorporate your favorite foods into a healthy diet.
If you want some "food for thought" about what triggers us to eat so much, I recommend the book "Mindless Eating" by Brian Wansink, Ph.D.
Basically, food is nutrition for our bodies. Period. But we humans attach lots of emotional associations to foods. If we are using food in an attempt to meet some emotional needs or avoid some emotional pain, then it becomes a lot easier to eat the food than to face whatever we're avoiding or to go out and find other ways to meet our emotional needs. You might find it helpful to try to sort out these extra associations you've attached to food. Some options:
You can try journalling -- write down what you eat every day and what you are feeling and thinking before and after you eat. After a while you might see a pattern, and once you figure out what's triggering you, you can look for other ways besides food to get your needs met.
You can go for a few visits to a cognitive therapist, where you can bounce some associations and concerns off of someone who's trained to help you look at things from other points of view.
Or -- How about taking a cooking class or two at your local adult education center or junior college? You can transfer your unhealthy "obsession" into a healthy "hobby".
This way you spend just as much time thinking about food, but you can do it in a much healthier way.