What foods are beneficial to a person who has upper Gastro-intestinal Cancer?

Foods that reduce the acidity in your body. If I were diagnosed as such I would eat as much watermelon as possible.

Not sure about food but manatek.com has a product called ambertose It is the sugars that our body doesn't get because food is so processed these sugars are cell communicators and help the body to heal itself check it out its worth living for

For this you need to speak directly with your oncologist and ask for a referral to a dietician. I had breast cancer. Good Luck.

Try a book called The pH Miracle Diet. I know a person with prostate cancer. He went on the diet, got no other treatment, and he is improving every time he goes for a PSA test. By all means, do whatever treatment your doctors think is necessary, but keep your body alkaline, not acidic. Meats cause acidity, along with some other foods, and veggies and fruits are by and large good.
http://www.energiseforlife.com/list_of_a...

That will give you an idea of what foods are good for keeping your body alkaline. And I highly recommend the book. I have seen it work. But please, do NOT stop any treatments you are currently getting. The book is worth it though. The person I know has lost that last few pounds, gained tons of energy, feels years younger. And is beating prostate cancer with no radiation, surgery etc.

http://www.amazon.com/pH-Miracle-Balance...

There are also "green foods" pills ( things you wouldn't dream of eating, but are good for you, like algea). That will help you out if there are times you don't feel like eating much.
I have no experience with GI cancer, but it has been said cancer can't grow in an alkaline body. It is worth a try.
Good luck, will keep you in my prayers.