4. Lower mTOR = Greater Autophagy
There is a great amount of recent research about protein complexes (enzyme) called mechanistic (or mammalian) target of rapamycin (mTOR). Essentially, mTOR is a nutrient sensor of dietary protein (amino acids). Eating protein raises mTOR levels triggering cellular growth. [10,12-13]
Fasting reduces mTOR which activates a “re-purpose and recycling” process called autophagy. [10,12,14] This is an internal housekeeping mechanism where old or damaged compounds (like proteins, organelles) are broken down into their basic building blocks (amino acids from proteins, fatty acids from fats) to be used to make new structures, make repairs or convert to energy. [12-14]
Autophagy happens in all tissues (muscle, cardiac), organs (liver, kidneys) and systems (CNS, endocrine). [10,1214] Besides clearing mis-folded proteins and cell debris, autophagy improves cellular and organ ability and has immense potential in treating diseases like atherosclerosis, Huntington’s, Alzheimer’s, Parkinson’s and cancer. [7,9-10,12-14]
5. Raise AMPK Boost the Energy
Repairs and other metabolic activity requires energy which is monitored by an enzyme called AMP-activated proven kinase (AMPK). AMPK is an energy sensor inside each cell that activates when ATP (adenosine triphosphate – body’s energy molecule) levels go down. [8,15-16]
AMPK boosts autophagy as well as energy producing pathways (production of ketone bodies and burning of glycogen and fat stores). [15-16] The growth phase is put on hold while key tissues (like nerves and muscle) are supplied with energy.
6. More Mitochondria Equals More Energy
Mitochondrion is an organelle inside a cell that produces energy (ATP and equivalent). Cells contain different amount of mitochondria. Intermittent fasting shown to increases mitochondrial biomass and output through several proteins and pathways.
These include BDNF, BHB (ketone) and PGC1-alpha which contribute to mitochondrial growth as well as their energy production capacity. [7-10] This all comes in handy during neuroplaticity and newly formed neural connections.
Latest fasting studies show mitochondria within cells link up into a network and work together to produce even more energy for longer.  Elevated human growth hormone (HGH) levels contribute to this phenomenon by providing much of starting material (through increased fat burning) inciting tissue mitochondria in producing more energy.