Frank, please check out http://www.dogfoodanalysis.com
It is a website that gives a break down of almost every type of dog food available. Perhaps now that your "outlaws" (just kidding...gf's parents) have a six year old dog, you may wish to look for a senior food.
May I also suggest that you investigate the Health Section of this Forum as many threads discuss feeding, including the one about Raw Feeding.
I believe that Bulldogs are prone to put on weight, particularly if given table scraps and low quality food. Exercise is required along with the right type of food to match the activity level.
I hope this is helpful.