Information by a researcher Don Layman. Very interesting. Only 7 minutes long.

https://www.youtube.com/watch?v=kdj0NpL_vJ4  #mce_temp_url#     

Edit: If you want a deep geeky dive listen to this one by Amber. I got a chance to meet her on a low carb cruise. She is studying all the time. A real geek. But she can cut a rut on a dance floor! This is NOT for those of you who just want cliff notes version. You know who you are! For those who like to learn new things, this will suffice. A really sharp lady. Most will not appreciate this, so just skip it.
https://www.youtube.com/watch?v=oel_RoEblzo  #mce_temp_url#