Shih-Tzu not eating

Question
My family and I adopted a tiny, 10 lb. Shih-Tzu from our local shelter about a year and a half ago.  We think she is about 8 years old and has definitely been spayed.  She is by far the most gentle, mild-mannered dog I have ever met.  She tolerates my 4 young children and their kind, but sometimes child-like behaviors very gracefully.  

We have taken her with us on at least 3 trips away from home since we've had her, (all by car; not plane.)  She does fabulous in the car, but being away from familiar surroundings does seem to stress her a little, and we understand now that she doesn't adapt to change well.  She typically won't eat normally for about 48 hours after being away, but then bounces back slowly.  Soon thereafter a completely normal eating pattern returns.  However, she still hasn't bounced back from our most recent trip last week.  We fully expected her to begin eating normally again within 48 hours of being away, but she didn't this time.  In fact, she ate very, VERY little the entire 9 days we were away.  Even after being back HOME for 3 days now, she is still not eating normally.  She will, however, accept treats when offered or some of her own food directly out of our hands; just not a full daily portion, and she won't eat out of her dish.  We are being very careful not to offer her more treats than usual, (2-3 a day,) to avoid replacing her appetite for regular food.  I honestly don't know how long I should let her continue this way before bringing her to the vet.  She's on a prescription diet for crystals in her urine, so I can't easily change her food.  Just as a sidenote:  she was eating complete normal, (about 3/4-1+ cup a day,) before we left for our trip and isn't showing any other signs of sickness.

Any tips you can offer would be helpful.
Thank you.
Julie B.

Answer
Far more dogs are harmed by their owners over feeding them than by their own not eating.  You may be over feeding it. A vet check still won't hurt. Many dogs will snarf down more than is good for them and look for more. Others refuse to eat more than than they need. Evaluate the dog as illustrated in this link, http://www.longliveyourdog.com/twoplus/RateYourDog.aspx  You may want the vet to confirm your judgment. Adjust the dogs food and exercise as needed to reach its ideal body condition. Some German Shepherds and other breeds may refuse to eat enough to completely hid their ribs. As long as you are feeding a concentrated, meat based chow, the best thing is to accept it.

The worst thing you can do is to bribe a dog with rich foods into eating more than it needs. Instead, 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.