AUTOPHAGY: Science-based discussion instead of mis-information and half-truths

AUTOPHAGY has become a hot health topic in the last couple of years, and as such, there's a lot of mis-information and half-truths, especially by the so-called health gurus on YouTube and various websites.  I thought it would be useful to cut thru all the BS and discuss this topic from a purely science-based, unbiased, and truthful perspective.

Just the basics for those who aren't sure what this is.  The cells of your body constantly breakdown and then recycle their parts.  In 2016 a Japanese cell biologist, Yoshinori Ohsumi, received the Nobel Prize in Medicine or Physiology for documenting the mechanism by which this occurs.  He was able to document precisely how cells breakdown and get rid of their waste.  This process is referred to as autophagy.  It comes form the latin terms "auto", meaning self and "phagein", meaning to eat.  So basically, autophagy is self-eating.

The first person to discover this process was Dr. Christian De Duve, a Belgian cytologist and biochemist, who was also awarded the Nobel Prize in 1974 for his discovery.  He discovered the cells have special recycling compartments, now referred to as "lysosomes".  They contain enzymes that consume worn out or damaged tissues, food particles, bacteria, viruses, and other junky materials and then these materials are transported out of the cell body and recycled into amino acids which can then be used for energy and to rebuild the body.  It goes on constantly in the body and is essential for survival.  This basically is autophagy.

In a typical day, the body needs to replace 200-280 grams of protein.  Even though the average person consumes far less than that, autophagy is able recycle junky materials such as dysfunctional proteins to meet the need.  

In starvation mode (or in a prolonged fast) when no protein is can be consumed and glycogen stores become depleted, the body will target proteins for fuel however, it targets proteins selectively.  Rather than target essential proteins such as those associated with the heart or skeletal muscle, it will seek out the junky materials in the lysosomes through the mechanism of autophagy. 

During starvation or a prolonged fast, once glycogen stores have become depleted, the body will target proteins (not stored fat) during the initial 48-72 hours of glycogen depletion.  Most people think that this means there will be a significant loss of muscle but that's not true.  Far less muscle is lost because autophagy  selectively targets the junky proteins stored in lysosomes first.  By the time these junky proteins have been consumed ands recycled, ketone bodies have begun to be produced in massive amounts and allow for stored body fat to be accessed and broken down into fatty acids to fuel the body, and the ketone body's themselves, since they can pass the blood-brain-barrier, can provide sufficient fuel to the brain, thus there is very little further catabolization of proteins after ketosis kicks in.

I am truly fascinated by the mechanisms of autophagy and ketosis, just form a science-based perspective.   I hope others are too.  I'm just posting this information as a teaser to spark discussion and debate.  There is a lot that is not known about autophagy, and a lot that is quite open to debate, and of course there is a HUGE amount of mis-information and half-truths associated with it, much of it courtesy of self-serving YouTube health-gurus and scammers.  I hope we can have a lively exchange SCIENCE-BASED information and debate.