If you're looking to lose weight, you HAVE to watch what you eat! I have read that "controlling your portion size is a key element in bringing your body to a state of controlled and manageable weight." I believe this to be true!! A few years ago when I lost just under 50lbs, watching what I ate played a major part in my weight loss.
I used a food journal and wrote down everything I ate/drank. I cut down my portion sizes to NORMAL servings and counted my calories. By counting calories and writing down exactly what I was eating and drinking, I could see where I needed improvement and how I could make the most of my calories. It didn't long to figure out I could eat more and feel more satisfied by cutting junk and replacing it with fruits and veggies.