Losing weight is discipline. I lost 30 lbs in a summer two years ago and last year during the biking season I was eating 3500 calories and still was not gaining weight. This is the first winter I am coming out of in a long time with less weight than I started. I am going to have to eat a really lot to keep up with my activities. I am at a ridiculous 15% body fat and I have not even begun to ride. I want to stay within 12 to 15 percent body fat so I have to eat a lot as I begin to ride and do my other warm weather stuff.
I walk or run almost every day for 3.5 miles. It is easy to do Walking I take 50 mins and running I take about 32. It feels really good to be in shape. I got in shape quickly by eliminating the breads, rice etc and processed foods. Stay away from the empty calories as in sodas etc and other sugary drinks.
I suggest you go to weight watchers for 6 months. It is only around 45 a month and you will learn good habits and how to keep track and discipline yourself. Plus you will get support in community (and behave around the fat girls even if they are easy pickings!).