What is Ketosis?
This short and simple post is part of a sequence of posts that are on the low-carbohydrate ketogenic lifestyle. Ketosis is an important term and it needs to be fairly understood by those who follow this type of lifestyle (in terms of nutrition).
Ketosis (often called nutritional ketosis) is the metabolic state where you body uses fat to create energy.
Most of the people are glucose dependent. This means that they use glucose to generate energy. Some consider this as the default state of the human body, while others think ketosis is.
Glucose is created from breaking down the carbohydrates that you eat. It can also be created by your body, in certain conditions and certain systems of the body.
When you are glucose dependent, your body uses little fat to create energy. Even under high physical exercise your body uses little fat.
For example, marathon runners bonk when they consume most of the glucose in their body. Bonking is the point of exhaustion when you don’t have the energy and the motivation to go further. Your body tends to crash.
How to Get into Ketosis?
Now, to reach ketosis (thus use fat for energy) one has to either fast or restrict carbohydrates. By fasting (not eating) you restrict carbohydrates as well.
When your body does not have the carbohydrates necessary to convert them to glucose which will be used for energy, it shifts to the second way to create energy, by breaking down fat.
When you give your body less than 50g of carbohydrates (some people need to have less than 30g, others need to have less than 20g – it depends), it will start breaking down fat into the liver and create ketone bodies. These ketone bodies are the by product of fat oxidation and they are: acetone, aceto-acetate, and beta-hidroxybutirate (BHB).
Ketosis is actually characterized by a level of 0.5 up to 5mmol/L of BHB in your blood.
It should not be confused with ketoacidosis which is often a Type 1 Diabetes condition where people have 10-15 times elevated serum ketones compared to nutritional ketosis, simultaneously with elevated blood glucose levels.
In nutritional ketosis, blood glucose levels as well as insulin remain fairly low while ketones are elevated. During prolonged fasting, insulin and blood glucose levels may further decrease (but never become inexistent) while ketones can further increase but mostly never reach dangerous levels.
So, when you’re restricting carbohydrates as mentioned above, you make your body use fat for energy. You practically use both the fat that you eat and also the fat that you have in your body storage.
I was in ketosis (and I still am) for more than 3 months now (as of Jan. 2014) . I actually had an experiment called “The Ketogenic Lifestyle” for the first two months. My body measurements and the DXA scans that I did before and after the experiment showed that I lost 4.2kg (~10 pounds) of fat during this time. Most of the fat that I lost was in the abdominal area. And I eat 60-70% fat, 20-30% proteins, and 5-10% carbohydrates.
In some of the follow up posts I’ll talk about the foods that you can eat to be in ketosis and the ones that you should avoid.
If there’s something you find intriguing or appealing in this post, just let me know in the comment sections below and I’ll try to get to the bottom of the problem.
1. Stephen Phinney and Jeff Volek – The Art and Science of Low Carbohydrate Living
2. Eric Westman, Stephen Phinney and Jeff Volek – New Atkins for a New You