You will still be able to eat after uncomplicated surgery. The location of the cancer determines what part needs to be removed. Note the oesophagus is the food pipe which takes the food to the stomach which is an organ that can stretch to accomodate a large meal and allow digestion to occur. For stomach/gastric cancer, sometimes the surgery may remove only part of the stomach organ, less commonly the whole stomach is removed (and the oesophagus is then joined directly to the small bowel). For oesophagus cancer, usually only part of the oesophagus and stomach is removed and the remaining oesophagus is joined to the remaining part of the stomach. Given this, ‘continuity’ is maintained in the gastro-intestinal tract so swallowed food will still pass through your bowels. Meal sizes will be altered and digestion can be affected, however the expectation is that after recovery you will continue to be able to eat well and function normally.