Hello, Diverticulitis disease is dangerous as there would have been recurrent infections that is why your colon surgery was performed to remove the segment with diverticuli. Once this surgery is done there is always a possibility that there may be a bit disruption in normal functioning of colon, there can be adhesion and kinking of small intestine and so on. These problems might have been the cause to give you the symptoms of feeling full and not feeling good if you eat less as it gives weakness. Hence I would advise you the following in such a situation: -Get contrast enhanced CT scan of abdomen to see for the possible causes and -Other tests of blood, stool and urine. All these will give a proper diagnosis and thus a proper management of the cause giving you better life. Hope I have answered your query. Let me know if I can assist you further. Regards, Dr. T Chandrakant