Sugar does not feed cancer, according to Mayo Clinic. While all cells depend on sugar for growth, there is no evidence to suggest that consuming sugar makes cancer cells grow faster.
Depriving the body's cells of sugar is not likely to slow the progression of cancer, either. It is believed that this myth arose after Positron Emission Technology (PET) scans began using sugar-based substances to image cancer cells. As PET scans show cancer cells absorbing sugar faster than other cells, some people may assume that sugar makes cancer grow faster.
Sugar consumption is a loose predisposing factor for some forms of cancer. For example, eating too much sugar contributes to obesity, which increases a person's risk of developing cancer.