Quitting Sugar and Heavily Processed Foods

I have struggled with my weight all of my life. My family was very poor growing up and I subsisted on a diet of heavily processed foods. I was heavy as a child and my weight has been fluctuating all my life. I've been married now for two years. My husband and I would like to start a family when we finish school in 1.5 years. I would like to lose about 50 pounds to be at my ideal weight before we start trying to concieve. As of now, I take fish oil, prenatels, and I am also on a light dose of Lexapro. I'm working on eliminating junky foods from my diet. I have a coffee in the morning and then just water and tea throughout the day. I am working up my cardio and strength training. Any other advice for prepregnancy weight loss and strengthening? I just want to give our future babies the best possible start.