When resources are scarce, cells turn on recycling programs and send garbage collectors known as lysosomes to engulf and digest junk proteins and damaged organelles, enabling re-use of their amino and fatty acids. (perfecthealthdiet.com)
What more non-essential source can we have than useless junk proteins floating around inside the cells?» (idmprogram.com)
To do this it makes use of free amino acids from the food you eat (Mark said lots of protein) plus junk proteins that you body is constantly recycling during cellular breakdown and repair. (gymjunkies.com)