12/18/2017
What is Ketosis
We have survived over 2 million years due to our ability to make ketones and during the majority of our existence people have been in ketosis. Most don’t realize that at numerous periods throughout the day, we are actually in ketosis, especially upon waking from a long nights sleep. Now a days, carb based foods are ubiquitous and most people show signs of metabolic dysfunction due to a carb heavy diet. In many, carbohydrate restriction that results in keto adaptation can correct this dysfunction.
We have evolved to store energy as fat; however, our brain did not evolve to use fat as energy, thus when releasing fatty acids for fuel we must convert them to ketones in the liver to be used by the brain. There are 2 ketones, beta-hydroxybutyrate and acetoacetate. These can be taken up by the brain and used as a fuel source. This process allowed us to develop larger brains. (Acetone is also a ketone, but is from the breakdown of acetoacetate, so not always discussed as a main ketone.)
The term ketosis literally means having ketones in the blood. Ketones are hepatically derived energy containing substances made from fatty acids that provide fuel for every cell in the body, except the liver.
In order to understand more about how the body uses ketones, let’s explore carbohydrate metabolism. Carbohydrates are derived from fruits, vegetables, sugar and grains. Carbohydrates are broken down into glucose. When glucose levels increase, insulin increases as well. When insulin levels are elevated we move to a fat storing state and any excess glucose is converted to fat. Initially we store this excess glucose as glycogen in the liver and muscle, but because our body can only store a few thousand calories as glycogen, we then move to fat storage. When we rely on glucose as our only fuel source, we can have many fluctuations of blood sugar. This is what leads to weight gain and cravings.
When we have a lack of glucose, glucagon is released into the blood stream, which triggers the release of glycogen (glucose). It also tells the body it’s time to use fat as a fuel source. When the body starts to burn fat for fuel, it must turn these fatty acids into ketones in the liver to be used as an energy source. It can take a few days or longer to get into ketosis, but once there the body will use fat as it’s main fuel source. This leads to an increase in satiety, decrease in hunger, weight loss and many other health benefits which we will discuss in future keto classes! We have learned through research that starvation is not the only way to move to a fat burning state. By eating a diet high in healthy fats and very low in carbohydrate, we can move to ketosis without feeling hungry or deprived. This is the ketogenic diet.
