So, what is a keto diet, and what exactly is Ketosis? The metabolic state of ketosis simply means that the quantity of ketone bodies in the blood have reached higher than normal levels. When the body is in a ketogenic state this means that lipid energy metabolism is intact. This means that the body will start breaking down your own body fat to fuel the body’s normal, every day functions.
For example, imagine that you are a member of a hunter gatherer tribe in ancient times. No grocery stores are available, and you have to hunt down and catch the food that you eat.
Unfortunately, for the past two days, you haven’t found any food animals to catch. No rabbits, no antelope, nothing. You are eating grass and leaves at this point, which are mostly fiber. You are in starvation mode.
What happens after your 1000 calories of glycogen are burned up? How does your body keep going when you don’t have any glucose or glycogen left?
That’s when ketosis happens.
During times when you can’t eat (like when you are sleeping, when no food is available, or just when you are busy) your body switches over to burning the fat stored from last week’s mammoth (or Twinkie) binge, and creates molecules called ketones, or ketone bodies.
The ketones can be used by your cells in place of the missing sugars, thanks to the body’s ability to switch metabolic pathways on the fly.
In other words, since you’ve burned up all your stored glycogen, and you don’t have any new food coming in, ketosis kicks in, and your body uses the fat that was stored from a previous meal to fuel itself.