Autophagy is a dynamic process in which damaged, old, or mutated cells break down into basic cell components through degradation. Deprivation of nutrients (e.g., fasting) stimulates autophagy, promoting cellular break down and the recycling of cellular components for cell survival. Fasting forces the body to find other sources of energy and building blocks and the body finds those sources in its own damaged cells. When the cells are recycled, they are broken down into components that can be used to power or create new cells. The basic components are:
Carbohydrates, which provide energy and structure for cells.
Nucleic acids, which contain all the instructions for all the cell activities.
Amino acids, which are the building blocks for proteins that do the work of the cell.
Lipids, or fats, which store energy and are the signaling and chemical identifiers of cells.
Breaking these old cells down into their components creates new immune cells, skin cells, brain cells, and every other cell in the body.
Shen, J.Z., Wu, G., Guo, S. (2021). Amino Acids in Autophagy: Regulation and Function. In: Wu, G. (eds) Amino Acids in Nutrition and Health. Advances in Experimental Medicine and Biology, vol 1332. Springer, Cham. https://doi.org/10.1007/978-3-030-74180-8_4