I am an overweight runner too.
I think running does help with weight loss, but it is not as simple as eat normally, go running, lose weight.
I have a very sedentary job, where I seem to use about one peanut's worth of calories every day. So if I starve myself eat sensible, small meals and no chocolate, and run, then I lose weight faster.
Also, I have noticed that I seem to be a bit thinner than last year, despite weighing the same. Maybe I have gained some muscle??
Another benefit of running, is that if I am having one of those days where I want to cram the entire fridge into my mouth, going running tends to change that.
Or if I am a bit down, a run will usually get me feeling more positive again, and less likely to comfort eat.
I lost about 4kg last year, so not a huge amount, but am hoping to carry on this year.
Wasnt there a huge survey published last year in teh states, where they followed the health of runners and non runners over about 20 years, and found huge health benefits in the runners group? IIRC, the non runners caused a few data collection problems, because too many of them inconveniently died during the 20 years.