While there are many different signaling factors in the “nutrient-sensing pathways” involved with cellular fasting, the 3 primary nutrient-sensing pathways that ProLon and fasting down-regulate are IGF-1, mTOR, and PKA. The process is complex, and each pathway can interact with other pathways, but in general, PKA responds primarily to sugar and carbohydrates, while IGF-1 is primarily responsive to protein (and more strongly triggered by animal protein), and mTOR is triggered by IGF-1 and amino acids. Sugar and carbohydrates (and to some extent caffeine) will activate PKA. These nutrient-sensing pathways all help regulate the cells’ growth cycles and stress-resistant “fasting” state.