I was, and remain, pretty overweight. After I graduated last year, I decided to make a lot of little changes to my eating and lifestyle, which has been working great. After a lot of research, I tried to figure out how I could cut out a lot of my bad eating, but not go crazy - I am a big food fan!
What I eventually realized was that small, obvious changes really do work wonders. I started running 3-5 times a week, only for about 30 minutes (2 miles), but the changes were obvious! I also did some minor things with my eating habits - I all but cut out soda, red meat, fried foods, any sort of white carb, sweets, etc. The key here is I still allow myself to have these things very occasionally (I allow myself to eat just about anything in social situations that involve eating with other people - this is a good compromise that keeps you satisfied with the unhealthy stuff).
I have lost about 50 pounds in the 6 or 7 months I have been doing this, and I think I am still losing today. Eventually, once my body totally adjusts to these smaller changes I made, I plan on increasing the severity of changes gradually, until my eating habits will hopefully be better permanently.