Otto Warburg discovered that cancer cells display a unique metabolic phenotype of lactate fermentation in the presence of oxygen. This phenotype, known as the Warburg effect, enables tumor visualization using fluorodeoxyglucose positron emission tomography (FDG-PET) scans owing to the elevated rate of glucose consumption in most cancers.
Metabolic therapies can exploit this phenotype, offering novel therapeutic directions aside from the classically targeted cytotoxic and gene-based therapies. The Warburg effect exposes a fundamental weakness of cancer cells, reliance on excess glucose for survival and maximal proliferation.
Fasting, calorie restriction (CR) and the carbohydrate-restricted ketogenic diet have been successfully used to limit glucose availability and slow cancer progression in a variety of animal models and human studies.1–9 These dietary manipulations produce a physiological metabolic shift to an unfavorable environment for glucose-dependent cancer cells.
Previously, the anticancer effects of these dietary manipulations have largely been attributed to decreased circulating blood glucose, which limits energy substrates for cancer cells. New evidence suggests, however, that the physiological state of ketosis and elevated circulating ketones also have anticancer effects.
This is why a PET scan works to locate cancer in the body.