Ketosis is a process that the body does on an everyday basis, regardless of the number of carbs you eat.
Your body adapts to what is put in it, processing different types of nutrients into the fuels that it needs. Proteins, fats, and carbs can all be processed for use. Eating a low carb, high fat diet just ramps up this process, which is a normal and safe chemical reaction.
When you eat carbohydrate based foods or excess amounts of protein, your body will break this down into sugar – known as glucose. Why? Glucose is needed in the creation of ATP (an energy molecule), which is a fuel that is needed for the daily activities and maintenance inside our bodies.
If you’ve ever used our keto calculator to determine your caloric needs, you will see that your body uses up quite a lot of calories. It’s true, our bodies use up much of the nutrients we intake just to maintain itself on a daily basis. If you eat enough food, there will likely be an excess of glucose that your body doesn’t need.
There are two main things that happen to excess glucose if your body doesn’t need it:
- Glycogenesis. Excess glucose will be converted to glycogen and stored in your liver and muscles. Estimates show that only about half of your daily energy can be stored as glycogen.
- Lipogenesis. If there’s already enough glycogen in your muscles and liver, any extra glucose will be converted into fats and stored.
So, what happens to you once your body has no more glucose or glycogen? Ketosis happens.
When your body has no access to food, like when you are sleeping or when you are on a ketogenic diet, the body will burn fat and create molecules called ketones. We can thank our body’s ability to switch metabolic pathways for that.
These ketones are created when the body breaks down fats, creating fatty acids and glycerol, and burned off in the liver in a process called beta-oxidation. The end result of this process is the creation of ketones, which are used as fuel by the muscles and brain.
Although glucose is the main source of fuel for most people, these fatty acids are used by the brain cells when carbohydrate or food intake is low. In simpler terms, since you have no more glucose or glycogen, ketosis kicks in and your body will use your stored/consumed fat as energy.
Ketosis is pretty amazing, and in fact, gets even better. Studies show that the body and brain actually prefer using ketones, being able to run 70% more efficiently than glucose. From an evolutionary standpoint, this makes perfect sense.
Our ancestors didn’t always have access to food, and they certainly didn’t always have access to glucose. Their body was feasting on the fat from the last wooly mammoth or saber-toothed tiger.
How Does Ketosis Work?
When fat is broken down by the liver, glycerol and fatty acid molecules are released. The fatty acid is broken down further, in a process called ketogenesis, and a ketone body called acetoacetate is produced.
Acetoacetate is then converted into 2 other types of ketone bodies:
- Beta-hydroxybutyrate (BHB) – After being keto-adapted for a while, your muscles will convert the acetoacetate into BHB as it’s preferred by the brain as fuel.
- Acetone – Can sometimes be metabolized into glucose, but is mostly excreted as waste. This gives the distinct smelly breath that most ketogenic dieters know.
Over time, your body will expel less excess ketone bodies (acetone), and if you use keto sticks to track your levels of ketosis, you may think it is slowing down.
That’s not the case, as your brain is burning the BHB as fuel, and your body is trying to give your brain as much efficient energy as possible. This is commonly why long-time low carbohydrate consumers will not show deep levels of ketosis on their urine tests.
The glycerol that was created will be converted into glucose in a process called gluconeogenesis. This is a normal metabolic process that creates glucose from the amino acids in protein, lactate from the muscles, and the glycerol from fatty acids.
Glucose is needed by the body, in small amounts, to maintain good health – but carbohydrates aren’t needed. Your liver will always make sure you have enough glucose in your bloodstream for the body to perform healthily, no matter what.
In fact, about 56% of excess protein will be turned into glucose in your blood stream – this is why too much protein is a bad thing and can knock you out of ketosis. Don’t worry – as long as you are following your macros, this will not be a problem for you.
As long as you are eating enough protein and fats each day, the liver can perform gluconeogenesis from the amino acids and fatty acids you ingest. This is important because if you are not eating enough protein, your muscle tissues will be burned to make the glucose that your body needs.
It’s also important to note that ketosis and starvation are two different things. Starvation happens when you have no food sources. Your body will start to convert the protein in your muscles to glucose, causing muscle loss.
Yes, you lose weight in starvation; your body also converts the fat in your stores to glucose in order to survive. But this is not healthy. Do you want to look like a ragdoll of skin and bones? Didn’t think so.
In normal states, we have fat stores to be used, and the ketogenic process will help us preserve our muscle tissue by using ketosis and the ketone bodies we create for fuel.