Donfoo, My husband was a diet controlled diabetic at the time of diagnosis, so we were very careful about the sugars in his diet throughout treatment. He made it through 5 weeks of radiation without the tube. He never went completely off of solid food, but towards the end used a ton shakes to get his nutrition. We were able to find a protein powder that had no sugar or carbs, all protein, that I would mix with cold milk, bananas, peanut butter and omega oils. It is possible to avoid sugar in the supplements. Post note, losing 50 lbs through treatment, he's no longer diabetic.