Sourdough is better than some of the more fancier breads but not much better than regular white, wholemeal or whole grain breads. For example, rye sourdough (per slice) is 68cal compered with No Name white 72cal, whole grain 71cal and wholemeal 69cal. Some makes of bread can be better like Buttercup Country Split 66cal, Fielders Daybake 64cal or Fielders Wholemeal 63cal. Overall not much difference really.
The thing with bread isn't so much what type but rather how much. When I was losing weight I cut right back on my bread. A few times a week I would have a slice when I had bacon (lean) and eggs for breakfast. For lunch I would have one slice with something on it. I cut bread out entirely for dinner. I pretty well keep to this routine even today.
Now: keeping it off for life!