Cancer as a Metabolic Disease
Cancer is not simply a collection of rapidly dividing cells. It is also a disease of profoundly altered cellular metabolism. One of the most reproducible metabolic features of malignancy is increased glucose uptake and glycolysis, known as the Warburg effect: many cancers consume glucose avidly and convert much of it to lactate, even when oxygen is plentiful (1,2). This is the same property that makes tumors light up on an FDG-PET scan, which uses a radiolabeled glucose analogue to locate metabolically active tissue.
This observation provides the rationale for using nutrition to modify the metabolic environment in which a tumor lives. It is worth being precise about what that means. The objective of a therapeutic ketogenic diet is not to “starve cancer” in any literal sense. Even when dietary carbohydrate falls to very low levels, the liver continues to manufacture glucose through gluconeogenesis, and blood glucose remains within the normal range (3). The real objective is to change the systemic metabolic terrain: to flatten glucose excursions, reduce insulin signaling, raise circulating ketones, and shift normal tissues toward greater reliance on fatty acids and ketone bodies (4,5).
Within a multi-axis metabolic approach, diet therefore serves as the foundation upon which other interventions are layered. Its central objectives are lowering systemic glucose, reducing insulin and IGF-1 signaling, activating AMPK, suppressing mTOR signaling, and imposing sustained metabolic stress on cells that depend heavily on glycolysis.
A necessary caveat. A sound biological rationale is not the same as proof of clinical benefit. Current human studies show that ketogenic diets reliably lower glucose and insulin and can usually produce nutritional ketosis. Whether these changes translate into longer progression-free or overall survival remains uncertain (6). The ketogenic diet is best understood as an adjunct to evidence-based cancer treatment, not a replacement for it.
