Disabled macroautophagy
The clean-up crew slows down
Cells eat their own broken parts and build new ones out of the pieces. It is the most efficient recycling scheme in nature, and it runs hardest when nothing is coming in. With age it slows, the rubbish stays where it falls, and a great deal of what ageing feels like from the inside is that pile.
This is the one that answers to a decision you make at breakfast. Leave a real gap without food — a shorter eating window, or a longer fast now and then — and the crew goes to work. Hard exercise calls them out too. Coffee, green tea and olive oil each nudge it along. Rapamycin is the strongest trigger we know of, and it is a prescription drug still under study.
The science, in one sentence
The cell’s bulk recycling system, which breaks down its own damaged parts so the material can be reused, becomes less active with age.