By Dr. Andreas Eenfeldt, MD – Updated October 2017
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, 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.
1. Ketosis explained
The “keto” in the word ketosis comes from the fact that it makes the body produce small fuel molecules called “ketones”.1 This is an alternative fuel for the body, used when blood sugar (glucose) is in short supply.
Ketones are produced if you eat very few carbs (that are broken down into blood sugar) and only moderate amounts of protein (excess protein can be converted to blood sugar).
Ketones are produced in the liver, from fat. They are then consumed as fuel in the body, including by the brain. This is important as the brain is a hungry organ that consumes lots of energy every day,2 and it can’t run on fat directly. It can only run on glucose… or ketones.
Maximizing fat burning
On a ketogenic diet your entire body switches its fuel supply to run almost entirely on fat. Insulin levels become very low and fat burning increases dramatically. It becomes easy to access your fat stores to burn them off. This is obviously great if you’re trying to lose weight, and studies show that ketogenic diets lead to more weight loss.3
But there are also other less obvious benefits.
When the body produces ketones it’s said to be in ketosis. The fastest way to get there is by fasting – not eating anything – but obviously it’s not possible to fast forever.
A low-carb or “keto” diet, on the other hand, can be eaten indefinitely and also results in ketosis. It has many of the benefits of fasting – including 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. That would make us waste away quickly. It would also ensure that the human race could hardly have survived all those millennia before we had 24-7 food availability.
Fortunately our bodies has evolved to be smarter than that. Normally we have fat stores that lasts 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.
2. 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.
READ MORE: Keto
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, 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.
1. Ketosis explained
The “keto” in the word ketosis comes from the fact that it makes the body produce small fuel molecules called “ketones”.1 This is an alternative fuel for the body, used when blood sugar (glucose) is in short supply.
Ketones are produced if you eat very few carbs (that are broken down into blood sugar) and only moderate amounts of protein (excess protein can be converted to blood sugar).
Ketones are produced in the liver, from fat. They are then consumed as fuel in the body, including by the brain. This is important as the brain is a hungry organ that consumes lots of energy every day,2 and it can’t run on fat directly. It can only run on glucose… or ketones.
Maximizing fat burning
On a ketogenic diet your entire body switches its fuel supply to run almost entirely on fat. Insulin levels become very low and fat burning increases dramatically. It becomes easy to access your fat stores to burn them off. This is obviously great if you’re trying to lose weight, and studies show that ketogenic diets lead to more weight loss.3
But there are also other less obvious benefits.
When the body produces ketones it’s said to be in ketosis. The fastest way to get there is by fasting – not eating anything – but obviously it’s not possible to fast forever.
A low-carb or “keto” diet, on the other hand, can be eaten indefinitely and also results in ketosis. It has many of the benefits of fasting – including 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. That would make us waste away quickly. It would also ensure that the human race could hardly have survived all those millennia before we had 24-7 food availability.
Fortunately our bodies has evolved to be smarter than that. Normally we have fat stores that lasts 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.
2. 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.
READ MORE: Keto