evidence: There are many myths and questions about sugar and cancer treatment. But what do cancer patients really need to know about sugar to make sure they’re getting the best diet during treatment? Here, I'll answer common questions I hear about sugar and cancer treatment. [...] Natural sugars, which are found in fruits and whole grains, are better choices for cancer patients. These are called complex carbohydrates. Your body breaks them down and turns them into sugar. The body processes complex carbohydrates at a slower rate than sugar from cakes, cookies, pies and candy. Sugar in sweets like these doesn’t have to be broken down and can cause your blood sugar to go up. [...] No. Eliminating all sugar from your diet can be challenging and unrealistic to sustain long-term.