What is my prognosis?

I am a 54 year old male, 6 foot, 235 pounds.  I have been having smelly diarrhea for some time now.  I will go to bed and within a few hours my belly will be rumbling so bad I can't sleep, followed by terrible flatulance.  My wife will hear the rumbling and ask me if I am hungry.  Then in the morning I will have very smelly diarrhea for several hours and floating stools.  I did some research and decided to try a low fat diet.  I have been keeping fat calories under 30% of total calories, and have totally controlled the symptoms.  My gastroenterologist says my tests are current and seem normal, but wants me to keep him informed of any changes.  I have an annual checkup with my internist in three weeks.  I have had a section of my colon removed 10 years ago due to it being necrotic.  I take 20 mg. of Prilosec per day for GERD.  My father passed away a couple years ago due to complications of malabsorbtion.  He was in his late '70s, but I seem to be about 15 years ahead of him in symptoms.  I had a CT scan of my pancreas and a colonoscopy a couple years ago.