I, too, agree that it is very difficult to find what will work while you sift through the myriad options people direct you to. Keep in mind, the basic (or newly revised, I should say) food pyramid as a guide. Another important thing to remember is that while you are going through chemo and/or radiation, radical changes in diet are a shock to your digestive system and entire body, for that matter. A comprehensive change from a carnivorous diet to pure vegan diet would take many months for a healthy person and would most likely not be beneficial to someone going through chemo and/or radiation until many months after treatmnent. A very important part of radical dietary change is to detox first and then gradually work in the new diet. Detoxing while undergoing chemo and/or radiation is not going to be a good thing as is heavy detoxing while active cancer is in your body. Refined sugar intake with active cancer is also not good. Get your sugar from fruits as much as possible until your body is somewhat cancer free.
Take regular mutlivitamins. Sublingual B-12 will help your damaged digestive tract absorb and use protein versus just pushing it through.
Beyond this basic information, always consult with a dietician/nutritionist and your medical oncologist on all diets and changes in diets.
Ed