Cancer cells are mainly dependent on glycolysis for their growth and survival. Dietary carbohydrates play a critical role in the growth and proliferation of cancer and a low-carbohydrate diet may help slow down the growth of tumours. However, the exact mechanisms behind this effect are unclear. This review study aimed to investigate the effect of fat mass and obesity-associated (FTO) gene in the association between dietary carbohydrates and cancer. This study was carried out using keywords such as polymorphism and/or cancer and/or dietary carbohydrate and/or FTO gene. PubMed and Science Direct databases were used to collect all related articles published from 1990 to 2018. Recent studies showed that the level of FTO gene expression in cancer cells is dramatically increased and may play a role in the growth of these cells through the regulation of the cellular metabolic pathways, including the phosphoinositide 3-kinases/protein kinaseB (PI3K/AKT) signaling pathway. Dietary carbohydrate may influence the FTO gene expression by eliminating the inhibitory effect of adenosine monophosphate-activated protein kinase (AMPK) on the FTO gene