High fiber diet leads to butyrate production in the colon by the action of butyrate-producing bacteria (depicted as yellow ovals), which is used by colonic epithelial cells as a primary source of energy. However, cancer cells use glucose to obtain energy and feed anaplerotic reactions (Warburg effect), leading to the accumulation of non-oxidized butyrate, which acts as a HDAC inhibitor, in turn increasing histone acetylation and expression of key pro-apoptotic and cell cycle regulatory genes suppressing tumor growth.