The Effect of Carbohydrates Intake, Free Sugars, and Ketogenic Diet on Cancer Development: Critical Review of the literature

In 1920, Otto Warburg established the Warburg Effect which is defined as the unusual fuel generation by the cancer cells through their dependence on glucose metabolism. The aim of the current review is to present the evidence for the association between cancer development and carbohydrate intake and the ketogenic diet usefulness for these patients. Search was conducted in PubMed, Scopes, and Wiley Online Library during 5th November 2021 to 1st December 2021 with searching terms of sugar and cancer, carbohydrates intake and cancer, the ketogenic diet and cancer. RefWorks was used for managing the references. One hundred and seventy studies were found based on inclusion criteria. There are limited metabolic ward randomized clinical trials (RCT) that investigated cancer development with carbohydrates intake, free sugar, or the ketogenic diet. Most studies used food frequency questionnaire (FFQ) as a dietary assessment tool for intake collection however, this method is not intended for this purpose. Results were inconsistent some studies reported carbohydrate intake with adverse effect on endometrial cancer, pancreatic cancer, or overall cancer. On the other hand, some studies reported no effect or a possible protective effect for fibers and low glycemic index carbohydrates. Overall, the relationship is debatable. However, carbohydrate is an important macronutrient for optimum health. In conclusion, there is not enough high-quality evidence to support the hypothesis of carbohydrates and free sugar association with cancer progression additionally the ketogenic diets studies had some limitations. This paper suggests the need for interventional metabolic ward studies with appropriate dietary assessment methods.