Cancer metabolism is a well-studied area in cancer biology, predating the discovery of oncogenes and tumor suppressors. Tumor cells reprogram their metabolic pathways to meet the bioenergetic, biosynthetic, and redox demands of malignant cells, a process known as metabolic reprogramming. This review provides a conceptual framework to understand how and why metabolic reprogramming occurs in tumor cells and the mechanisms linking altered metabolism to tumorigenesis and metastasis. Key principles include the enhanced activity of glycolysis, tricarboxylic acid (TCA) cycle intermediates, and anaplerotic pathways, which support anabolic growth and cell survival under nutrient-replete or limited conditions. The role of signaling pathways such as PI3K-AKT-mTOR in regulating these metabolic pathways is also discussed. Oncometabolites, metabolites that accumulate in tumors due to specific mutations, are another important aspect of cancer metabolism, with examples like 2-hydroxyglutarate (D2HG) and fumarate/Succinate playing roles in epigenetic regulation and tumor progression. The review highlights the importance of bioenergetics, biosynthesis of macromolecules, and redox balance in cancer, and discusses potential therapeutic targets, such as LDH-A, HK2, PHGDH, and mitochondrial metabolism, which could be exploited for cancer treatment.Cancer metabolism is a well-studied area in cancer biology, predating the discovery of oncogenes and tumor suppressors. Tumor cells reprogram their metabolic pathways to meet the bioenergetic, biosynthetic, and redox demands of malignant cells, a process known as metabolic reprogramming. This review provides a conceptual framework to understand how and why metabolic reprogramming occurs in tumor cells and the mechanisms linking altered metabolism to tumorigenesis and metastasis. Key principles include the enhanced activity of glycolysis, tricarboxylic acid (TCA) cycle intermediates, and anaplerotic pathways, which support anabolic growth and cell survival under nutrient-replete or limited conditions. The role of signaling pathways such as PI3K-AKT-mTOR in regulating these metabolic pathways is also discussed. Oncometabolites, metabolites that accumulate in tumors due to specific mutations, are another important aspect of cancer metabolism, with examples like 2-hydroxyglutarate (D2HG) and fumarate/Succinate playing roles in epigenetic regulation and tumor progression. The review highlights the importance of bioenergetics, biosynthesis of macromolecules, and redox balance in cancer, and discusses potential therapeutic targets, such as LDH-A, HK2, PHGDH, and mitochondrial metabolism, which could be exploited for cancer treatment.