Crux of Is there a role for carbohydrate restriction in the treatment and prevention of cancer? by Rainer J Klement and Ulrike Kämmerer:

Carbohydrates promote cancer, restricting carbs in the diet can delay or prevent tumor growth.

There are several mechanisms for this:

  • While regular cells can use both carbs and fat for energy, “most malignant cells depend on steady glucose availability in the blood for their energy […] due to mitochondrial dysfunction.” So while eating fats feeds only normal cells, eating carbs feeds the cancer cells.
  • Eating carbs causes elevated levels of insulin and insulin-like growth factor (IGF), and these hormones “can directly promote tumor cell proliferation via the insulin/IGF1 signaling pathway.”
  • When the body uses fat for energy, it creates ketones. High ketone levels “have been found to negatively affect proliferation of different malignant cells in vitro”.
  • High levels of glucose in the blood (caused by eating carbs) “impair the transport of ascorbic acid [vitamin C] into immune cells […] so that the immune response to malignant cells is diminished.”
  • It also “activates monocytes and macrophages to produce inflammatory cytokines that play an important role also for the progression of cancer.”
  • “Another potential benefit of low [carb] diets might lie in their influence upon inflammatory processes that take place within various tissues. Inflammation is a well-established driver of early tumorigenesis and accompanies most, if not all cancers.”