Biochemistry of Obesity - Normal Glucose Metabolism

Glucose is the basic fuel for living organisms, from bacteria to humans, and is the primary energy source for your brain. It is a product of photosynthesis and is found in rice, corn and other grains, and bread and pasta.
Once you take in glucose from a meal -- like, say, from two slices of bread -- 80 percent of it is used by all of the organs of your body -- every single cell. The remaining 20 percent goes to your liver to be metabolized and stored.

The following is what happens to that 20 percent, once it reaches your liver:

• Whatever glucose your body doesn’t need immediately gets converted into glycogen for storage in the liver. Glycogen is your body’s non-toxic short-term energy storage package, where it can be easily converted to energy when you need it. Your liver has no limit to how much glycogen it can store without detrimental effects. (That is what athletes take advantage of when they “carb-load.”)
• 
  · A small amount of pyruvate is produced, which ends up being converted to ATP (the chemical storage form of energy) and carbon dioxide. An even smaller quantity of citrate is produced from this process through the “citrate shuttle,” which ends up as VLDL (very low density lipoproteins, the bad ones) in a process known as de novo lipogenesis -- but we’re talking about a very small amount (less than one calorie from two slices of bread).
• 
  · Insulin is released by your pancreas in response to the rise in blood glucose (i.e., blood sugar), which helps the glucose get into your cells. Without insulin, your cells would not be able to process the glucose and therefore would have no energy for movement, growth, repair, or other functions. Insulin is key to unlocking the door of the cell to allow the glucose to be transferred from the bloodstream into the cell.

· When you consume 120 calories of glucose, less than one calorie contributes to adverse metabolic outcomes.

This is all very normal, and it’s how you were designed to operate.