What Happens to your Body when it’s in Ketosis?

A ketogenic diet is a very low-carbohydrate diet that pushes your body into ketosis. But what’s ketosis exactly?

“Ketosis” technically refers to the condition of high ketone levels in the blood. In a more general sense, the word “ketosis” describes a metabolic state in which you run on ketones.

Learn more about what happens to your body when you switch to a keto eating plan and achieve this different metabolic state.

Salmon meat contains no carbohydrates and can be consumed on a keto diet; image source: pexels.com

Ketosis in a nutshell

A person on a standard diet burns glucose for energy. This state is called “glycolysis.”

When you start eating fewer carbohydrates and less sugar, your body burns through its reserves of glycogen. Glycogen is simply a compact form of glucose that’s stored in your muscles and liver.

As glycogen diminishes, your cells no longer get enough of the fuel they’re used to. Desperate for energy, your body turns to fat.

But you don’t get energy directly from fat. Your liver breaks fat down into ketones. These are the molecules that actually fuel your body when you “burn” fat.

How your body compares to a Prius

Here’s a loose analogy to explain ketosis: Compare your body to a hybrid vehicle.

Like most hybrid owners, you usually prefer to run your car on electricity because it’s a cleaner source of energy than gas is. But then one weekend, you decide to head out across the desert on a road trip.

Eventually, your battery becomes discharged. Because there’s no charging station around, you have to switch over to gas.

In a similar way, your body was built with two fuel systems. Being able to survive on both sugar and fat is an extraordinary survival mechanism.

Sugar; image source: pexels.com

Fat for fuel: plan A or plan B?

Scientists disagree on which system is primary. Many people assume that sugar burning is the normal metabolic mode. This is mostly because we’re accustomed to the typical carb-laden diet, which our recent ancestors ate as well.

In fact, proponents of ketogenic and low-carb diets purport that the body was designed to run more efficiently on fat and protein. Backing this up is the fact that your body needs certain proteins and fats to survive.

But there are no essential carbohydrates. Your body needs very little glucose and can extract what it does need from even foods that contain few carbs.

How to know when you’re in ketosis

When your body reaches ketosis, you may or may not notice the change. You can look for a few telltale signs, but you may not always find them.

Some people notice a change in their breath or body odor. This is caused by acetone, one type of ketone, but disappears within about a week.

Your body sheds excess water when it depletes its glycogen and glucose stores. You may experience frequent urination and lose several pounds in the first few days of a fast or low-carb diet.

If you’re switching from a high-fiber diet to a ketogenic diet, you may notice a change in your bowel movements. Drink plenty of water, eat vegetables, and add a fiber supplement such as psyllium husk, ground flaxseed, or glucomannan.

Flax seeds; image source: empoweredsustenance.com

Low energy may occur as your body switches gears from burning sugar to burning fat.

If you’re plagued by sugar cravings, don’t give up. This is a typical side effect of changing over to a ketogenic diet. The cravings will disappear within a few days.

Why you should start your keto diet on Friday

Most of the unpleasant symptoms of ketosis disappear within a few days. That’s why you’d be smart to start your new eating plan on a Friday.

You likely won’t notice any negative effects until the end of the day. Then you’ll have all weekend to deal with the changes. By Monday, you may already notice an improvement in your energy levels.

What ketosis is not

When you’re throwing the term “ketosis” around, it’s important not to mistakenly use “ketoacidosis.”

Ketoacidosis occurs when a person’s blood sugar level AND ketone level are both elevated. This state is a dangerous complication of uncontrolled diabetes.

When diabetic ketoacidosis occurs, the blood becomes highly acidic. This change in pH can harm organs such as the kidneys and liver.

As you now know, if a healthy person is in ketosis, their blood sugar level should be quite low. Carefully managed ketosis is not harmful and actually benefits the body.

Ketosis wrap-up

You’ve learned a lot about ketosis, but the takeaway is simple: Ketosis equals fat-burning.

A lot happens to your body while it transitions into this fat-burning state. However, the main thing that happens when you reach the ketotic state is that you burn more fat and lose weight more easily.


  1. Keto diet should always be associated with a healthy lifestyle and lot of exercise to burn those unnecessary fats. Living a healthy lifestyle and eating foods rich in amino acids will provide the nutrients you need in your body.

  2. Doing keto diet is a serious plan to do. There are such preparations that we need to have, because we all don\’t know what\’s gonna happens next. It is better to be ready than sorry.

  3. Keto is quite hard to maintain. Many people that I know have given up simply because it weakens them. Fortunately, I also know some who got slim because of keto. I guess that people just stick to whatever diet suits them best.

  4. I am still trying to decide whether to embrace the keto diet or not. I understand that this type of diet is not for everyone. One has to be mentally prepared if he wants to embark on this journey.


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