The Warburg Effect, observed in cancer cells, involves increased glucose uptake and fermentation to lactate, even in the presence of fully functioning mitochondria. This phenomenon has been studied extensively for over 90 years, but its precise function remains unclear. The authors analyze several proposed biological explanations for the Warburg Effect, including rapid ATP synthesis, biosynthesis, tumor microenvironment effects, and cell signaling. They discuss the rationale and controversies surrounding each proposal, highlighting the challenges in understanding the Warburg Effect's role in cancer growth and survival. Despite extensive research, the Warburg Effect's functions remain controversial, and further studies are needed to elucidate its true benefits for tumor cells.The Warburg Effect, observed in cancer cells, involves increased glucose uptake and fermentation to lactate, even in the presence of fully functioning mitochondria. This phenomenon has been studied extensively for over 90 years, but its precise function remains unclear. The authors analyze several proposed biological explanations for the Warburg Effect, including rapid ATP synthesis, biosynthesis, tumor microenvironment effects, and cell signaling. They discuss the rationale and controversies surrounding each proposal, highlighting the challenges in understanding the Warburg Effect's role in cancer growth and survival. Despite extensive research, the Warburg Effect's functions remain controversial, and further studies are needed to elucidate its true benefits for tumor cells.