What is Ketosis
Ketosis is a natural state for the body, when it is almost completely fueled by fat. This is normal during fasting, or when on a strict low-carb diet, also called a keto diet.
Ketosis has many potential benefits – related to rapid weight loss, health or performance – but there are also side effects. In type 1 diabetes and certain other rare situations excessive ketosis can even become dangerous.
On this page you can learn all about how to harness the benefits of ketosis, while avoiding any problems. It all starts with understanding what ketosis is.
The “keto” in the word ketosis comes from “ketones”, the name of small fuel molecules in the body. This is an alternative fuel for the body, produced from fat we eat, and used when blood sugar (glucose) is in short supply.
These ketones are produced when you eat very few carbs (the main source of blood sugar) and only moderate amounts of protein (excess protein is converted to blood sugar).
Under these circumstances, fat is converted in the liver to ketones, that then enter the blood stream. They are then used as fuel by cells in the body, just like glucose. They can even be used by the brain. This is extra important, as the brain can not be directly fuelled by fat, and it’s a very hungry organ.
Maximizing fat burning
Under these circumstances, as soon as the body’s limited reserves of glucose starts to run out, your entire body switches its fuel supply to run almost completely on fat. The levels of the fat-storing hormone insulin levels become very low, and fat burning increases dramatically. You thus get easy access your fat stores, and can burn them off. This is great for losing excess weight. Studies prove that keto diets result in more weight loss, faster. There are also more potential benefits.
When the body produces enough ketones to measure significant levels in the blood (usually over 0.5 mM) it’s said to be in ketosis. The fastest way to achieve ketosis is by fasting – not eating any food – but that’s not possible to do forever.
A strictly low-carb or “keto” diet, however, can be eaten for any amount of time. It also results in ketosis. It achieves many of the benefits of fasting – like weight loss – without having to fast
Ketones are brain fuel
It’s a common misconception that the brain needs carbs. The truth is that the brain happily burns carbs when you eat them. But if you don’t eat too many carbs, the brain is happy to burn ketones instead.
This is an absolutely necessary function for basic survival. As the body can only store carbs for a day or two, the brain would quickly shut down after a couple of days without food. Alternatively it would quickly have to convert our muscle protein into glucose – a very inefficient process – just to keep the brain going.
Normally we have fat stores that last so that we can survive for many weeks (if not months) without food. Ketosis is how the body makes sure that the brain can run on those fat stores too.
Bottom line: We do not need to eat any carbs at all. The brain can happily run on fat.
Many people even feel more energized and focused when the brain gets to run on ketones, made from fat. And it certainly speeds up fat loss, if you’re trying to lose weight.
The benefits of ketosis
There are many benefits of ketosis. By giving your body and brain an almost unlimited supply of energy, you can increase your mental and physical endurance. It also reduces hunger, facilitating effortless weight loss.
Furthermore, as getting into ketosis requires eating very few carbs, it can effectively reverse type 2 diabetes. Ketosis has also been used for a long time to control epilepsy – often even without drugs.
Even beyond this, it’s showing great promise for several other conditions, like improving acne, reversing PCOS and perhaps even treating brain cancer.
How to get into ketosis
To get into ketosis you need low levels of the fat-storing hormone insulin. The most important way to do that is to eat a strict low-carb diet, also called a ketogenic diet.
On top of the necessary ketogenic diet there are many ways to increase ketosis further. The most powerful is adding intermittent fasting.
How do you measure ketosis
There are three ways to measure for ketones, which all come with pros and cons:
Breath ketone analyzers
Blood ketone meter
How to reach maximum ketosis
Getting into ketosis is not a black or white thing. It’s not like you’re either in ketosis, or out of ketosis. Instead, you can be in different degrees of ketosis, as this chart demonstrates. The numbers below refer to values when testing blood ketone levels.