GSD has intermittent diarrhoea

Question
Hi, We have a 8 month old female GSD, which suffered Gastro-Enteritis at 3 months of age. It was very severe, after recovering from it,she has had constant problems of intermittent diarrhoea(like once or twice every week). That is, every time there was some addition to her diet(like chews or rawhide bones), she would pass loose stools.  Now, we try and maintain her diet to just Rice, minced chicken and eggs, and pedigree dog food. She seems to be doing a little better, but still has loose stools whenever something new is given to her. What can i do to stablize her condition?
And, my vet did a stool test for her, the results showed that the fat content in her stools were a little high, my Vet also did mention that she might been having a slight defect with her pancreas,and everything else was normal. Please help.

Secondly,these days she does not seem to finish off her meal completely like before, Rice and eggs or even Pedigree. However she would clean up the bowl when Rice and minced chicken is given to her, which is twice a week.
She goes on for a few days like that and then she is ok. I am not able to understand her behaviour. Could it be because its almost time she had her first heat cycle? Please advice. Thanks a lot for any insight.  

Answer
Cut out everything except the Pedigree, no rice, no minced chicken, and above all, no rawhide or other consumable chews.  Rawhide and consumable chews not only lead to digestive problems, but can cause choking or intestinal blockages. I hope you haven't been feeding her any of that stuff raw.  That can lead to infections and more digestive problems.  Let her stomach settle down to a regular diet of dog chow.  The Pedigree and other dog chows are carefully formulated to provide the complete and balanced diet dogs need.  It is very risky to allow much of dog's diet to come from other sources.  

Shepherds are notorious light eaters.  You may have spoiled her with the rich food.  It may take some work to discipline her to eat a healthy diet of dry dog chow and nothing else.  Put down the dish with what the dog should eat, and give it 15 minutes to eat. Then take it up. Do not give it anything to eat until its next scheduled meal. In a few days, it should be eating what it needs. Continue to check its ribs and adjust the food as needed. This is not easy. I had a Shepherd go 3 days on a few nibbles. I was a wreck, but she was fine. It is almost unknown for a healthy dog not to eat what it needs. Unfortunately, in too many cases, it is less than the package says, and less than the owner thinks the dog should have. Many dogs are quite good at holding out for tastier chow. Like kids, sometimes it calls for tough love.  I once had a Shepherd go 3 days on a few nibbles.  I was a wreck, but it didn't hurt her a bit.  As long as her ribs only show a little, she will be fine.  That is quite normal and healthy with young Shepherds.  

Spay her now.  I hope you weren't thinking of breeding her.  You want to pass on her digestive problems to others?  We don't have a shortage of people breeding German Shepherds.  The breed has been badly damaged by people unknowingly or not caring breeding dogs that were not suitable breeding stock.  What we have a critical shortage of is homes for the dogs that are being bred.  At least go to www.akc.org and read what they say on responsible breeding.  Also see how many German Shepherds in your area needing homes are listed at www.petfinders.org?