Insulin and Fat Storage
Many people refer to insulin as the fat storing hormone, but it is important to understand where this comes from. Remember, insulin’s primary job is to lower blood sugar and get it into the cell where it can be used for energy.
Along with this, it also helps the cellular intake of amino acids and other nutrients. Insulin resistance can result in large amounts of blood sugar that cannot be used.
At first glance, this may seem like a good thing. After all, if the body can’t use sugar well, then surely won’t it begin to use its fat stores? Unfortunately, this is not how it works.
Insulin has very strong effects on fat partitioning. It is useful to take a historical frame of reference in regard to insulin. Human physiology is designed for a feast and famine existence. Modern times are a completely different situation, leaving ancient metabolic processes face-to-face with the reality of fast food and food on every corner.
When confronted with excess food insulin is released to get the nutrients into the cell to be burned. It also wants to save any leftover for a rainy day. So, it interacts with two key fat burning and storing enzymes: lipoprotein lipase (LPL) and hormone sensitive lipase (HSL). This is where the fat storing action of insulin becomes prominent.
On your fat cells LPL works to break down the triglyceride molecule (three fats attached to a glycerol backbone) to individual fats so they can be stored in the cell. HSL does the opposite, breaking down triglycerides in the cell so the fat can be released and burned.
Insulin is a powerful stimulator of LPL and a powerful inhibitor of HSL. So, as insulin levels rise in the body they not only increase fat storage, but perhaps more importantly block fat breakdown. This results in the body being almost completely reliant on sugar burning for energy, creating a physiology that refuses to burn any fat despite having much to spare.
Adding insult to injury, the liver is making so much sugar the body will liberate muscle protein instead of fat to aid this increased glucose production. The result is a body that is storing fat at a frantic pace, but at the same time losing muscle.