How Long Does it Take to Get Into Ketosis and Keto-Adapt? | H.V.M.N. Blog

Updated Dec 10, 2019
Brady Holmer

You’ve likely heard of the three major macronutrients that provide us with energy: protein, carbohydrates, and fat. However, our bodies can use another substrate as a source of energy, a “fourth fuel” called ketones. Ketones are produced (and sometimes supplemented) when the body is in a metabolic state of ketosis; one where it’s breaking down or burning fat.

Interestingly, while ketosis is said to be an evolutionary adaptation that allows organisms to survive under conditions of low food availability, newer research is showing that ketones have several diverse and impressive biological roles in the body, and many health benefits. They’re more than just an energy source.

People are becoming aware of the many applications of ketosis—including weight loss, sports performance, and cognitive function. However, many people might not be aware of how to get into ketosis, how long it takes, and what happens when you do.

This article provides all the information you need about entering and staying in ketosis.

Endogenous vs. Exogenous Ketosis

Before we talk about the specific ways to achieve ketosis, let’s go over some basics. Ketosis can be classified in two ways; endogenous (meaning “within”) or exogenous (meaning from “outside”). We will only cover some of the basics here, but feel free to check out our in depth article on the fundamentals of ketosis.

When we talk about endogenous ketosis, we are referring to the process of the body producing ketones on its own. This happens in the liver. When glucose levels in our body run low and insulin falls, our body begins to burn fat. Free fatty acids (FFAs)—the breakdown products of fat—are then transported to the liver and used to produce ketone bodies. These ketone bodies are then transported back out of the liver, where they travel through the circulation to organs and tissues to be used for energy.

In contrast, exogenous ketosis is achieved through the use of exogenous ketone supplements or precursors to ketone bodies like medium-chain triglycerides (MCTs). In exogenous ketosis, your body isn’t producing ketones, but is still in ketosis. There are many examples of exogenous ketones, which we will cover below.

Regardless of the method used, ketosis is ketosis. However, there are benefits specific to exogenous and endogenous ketosis. Some of this has to do with how long it takes to actually enter ketosis through each route. Generally, endogenous ketosis is going to take much longer, while exogenous ketosis can be achieved within a matter of minutes.

Before going into specific methods for getting into ketosis, let’s take a look at how you can verify that you’re actually in ketosis.

Testing for Ketosis

There is only one true way to confirm that you’re in ketosis—measuring ketones. This will allow you to quantify your level of ketosis using commercially-available devices.

Traditionally, ketosis is considered to occur when blood ketone levels of the ketone body known as beta-hydroxybutyrate (BHB) are >0.5 millimolar (mM).

The only way to verify this is to test for BHB. Blood BHB can be measured using a blood ketone meter. This device is similar to a blood glucose meter, except it measures ketones instead of glucose. There are several great ketone meters on the market, which we reviewed in this post.

The main advantage of testing for blood BHB is accuracy. Furthermore, blood levels of BHB represent the ketones you’re actually using, and BHB is the ketone body most present throughout the circulation.

However, testing for BHB does require you to prick your finger and draw blood—which can be a downside for some people. If you’re testing often, blood testing can also get expensive, since you’ll need to continuously purchase ketone testing strips for the device.

Ketosis can be measured using two other methods. To measure acetoacetate (AcAc), urine ketone test strips can be used. These measure the amount of AcAc in your urine. Urine test strips are easy and non-invasive, making them attractive to people looking for a simple way to test ketones.

Acetone, the third ketone body, can be measured in the breath using a device known as a breathalyzer. This method simply involves breathing into the device and getting a reading on your level of ketosis.