Going for losing 15 pounds!

I have tried to lose these last 15 post baby pounds for the last 6 years. My youngest is 6.5... I had an accident 3 years ago and shattered my tibia. Now my leg is healed but I have injury induced osteoarthritis in my left knee. It is basically bone on bone. I'm too young for a knee replacement. They say extra weight really has an negative impact on your joints. If I lose this 15 lbs to 20 pounds which would put me in an acceptable weight range will some of my pain go away? I figure it's maybe my best shot. I'm going to need help though. I lead a stressful life and I'm prone to bad eating to release the stress. They say keeping a food diary is one of the best things to do to help. I know feeling full and sated will be a factor and also pre planning. I'd also like my food to taste good!