Cellular Health
AMPK
AMPK, short for AMP-activated protein kinase, is the cell's main energy sensor. It monitors the ratio of spent to available fuel inside the cell, and when energy runs low, AMPK switches on to restore the balance. It does this by turning up the processes that generate energy and turning down the ones that consume it on building and storage.
This is what ties AMPK to fasting. As fuel becomes scarce during a fast, AMPK activity rises. Active AMPK then does two things that matter here: it helps switch cells over to burning fat for fuel, and it suppresses mTOR, the growth pathway that holds the cell's recycling process in check. AMPK rising and mTOR falling are two sides of the same shift, which is why they are best understood together rather than in isolation.
AMPK also promotes the upkeep of mitochondria, the structures that produce energy inside cells, which is part of why the fasted state is associated with a move toward cellular maintenance rather than growth.
