I would say that running helps you lose weight/ keeps you from gaining weight.
Without diet and other lifestyle changes, the sport alone is not a silver bullet. Find research on the behaviors/actions of people who have successfully lost or maintained their desired weight over the long term (2+ years). As I recall, people who support a low/healthy weight tend to exercise regularly, but (aerobic) exercise alone is not the cause of significant weight loss.
I know that when I started running more seriously and set myself a moderately challenging running goal, I had to change my diet, add energy promoted supplement, alcohol consumption, and sleep habits to achieve my goal. The positive results translated into the proper cycle.