Pick up this book. Amazon has it for $9.35 before shipping.

Lights Out: Sleep, Sugar, and Survival (2000) [ goodreads ]

introduction page 2 [ pic 1 ]

introduction pages 2 & 3 [ pic 2 ]

random paragraph from the above goodreads link:

When we don’t get enough sleep in sync with seasonal light exposure, we fundamentally alter a balance of nature that has been programmed into our physiology since day one. This delicate biological rhythm rules the hormones and neurotransmitters that determine appetite, fertility, and mental and physical health. When we rely on artificial light to extend our day until 11 p.m., midnight, and beyond, we fool our bodies into living in a perpetual state of summer. Anticipating the scarce food supply and forced inactivity of winter, our bodies begin storing fat and slowing metabolism to sustain us through the months of hibernation and hunger that never arrive. Our own survival instinct, honed over millennia, is now killing us.