life after total gastrectomy,intestinal pain after eating, food aversion, weight loss

My mom had total gastrectomy after being diagnozed with stage 3B stomach cancer in Sep 2008. Little by little after that she managed to get into an eating regimen and was doing OK. However few months ago, about 2 and 1/2 years post surgery she started experiencing some intestinal pain after eating, describing that the "food feels like a ball moving through the intestines", some more acid and heartburn and constipation. Cannot be correlated to any particular food type. Because of these unpleasant episodes she gradually decreased her eagerness to eat and also became a very picky eater. And of course that is leading to the scary weight loss... Has anyone experienced that and have you found a way to deal with it? Docs are not very helpful unfortunately. We are trying everything we can, but she needs to get her pounds back. And do you know if more fiber is good for people with total gastrectomy, I read conflicting reports on this on the internet. Any suggestions will be appreciated.