How Do You Know You’re in Ketosis And What Does It Feel Like?

The main goal of the Ketogenic diet is to keep the body in ketosis for the period of the diet. Ketosis, basically, means a metabolic state in which the levels of ketone bodies in the body tissue is raised, as a result of low carbohydrates. 

While on the keto diet, going over the required carbohydrate can or not maintaining the adequate protein intake can easily knock you out of ketosis. 

 The keto diet will easily make you feel like a brand new person; when your body is efficiently fueling on fats and your cells are running on ketone, you will be right on your way to greater well-being, and quicker weight loss.

So, what does Ketosis feel like?


As a newbie dieter or even if you’ve been on the diet for a while, there are some changes that your body will experience, and with these, you will know that you are in Ketosis.

Fatigue and Exhaustion

Young depressed women sitting in bed with her hand on face

When your body starts to newly adapt to the changes in the new diet, you may experience more exhaustion, tiredness, and feel more fatigued. As your body begins to switch from burning carbohydrates to burning fats, you feel more tired. 

Typically, your ingestion of carbohydrates provides a quick burst of energy to your body, as a result of the lack of this quick energy bursts, you feel more exhausted. This is mostly as a result of the switch in eating habits that your body is experiencing. 

As your body starts to adapt to this new lifestyle, you will soon start to feel more energetic. Your keto nutrients – Ketone bodies and fat, are a much more efficient fuel source than carbohydrates.



Another way to know that your body is in Ketosis is the feeling of thirst. When your body is in ketosis, your system is flushing out way more water than usual, resulting in thirst. You may also experience yourself drinking more water than usual because of the loss of electrolytes your body is experiencing.

Although you may assume that because of the frequent trips to the bathroom, you should drink less water, it is absolutely necessary that you keep your body from dehydrating by ingesting enough “acceptable” liquids. You will easily find drinks and supplements that’ll help replenish electrolytes that your body is losing.

Focus and Concentration


According to (2018), initial stages of the keto diet might cause fatigue and concentration difficulties due to the change in lifestyle, but over time, people who follow a long-term keto diet start to experience better clarity and focus. 

A systematic review by Van Berkel et al., (2018) found that some patients with epilepsy, when started on ketogenic diet report better alertness and attention when presented with cognitive tests.

Not only have these authors asserted to the benefits of ketosis, some other  , Hallböök et al., (2012) have also proven that over time, those who are on a long-term keto diet, experience enhanced cognitive function and neuroprotective effects. 

They showed that long-term ketosis can influence better sleep, memory, clarity, and concentration. Another study examining the effect ketones have on mitochondrial disorders as conducted by Frey et al., (2017) showed that being on ketosis can improve mitochondria functioning.

Weight Loss


A lot of people get on the keto diet in hopes to lose weight. The good news is, if you are doing keto right, you are likely to lose weight. You may notice sudden weight loss on the first few days of starting the diet, but this is usually a result of a reduction in water weight. 

People on the keto diet may start to notice true fat loss weeks after beginning the low-carb lifestyle. When you are on this very-low-carbohydrate diet, weight loss is a common symptom that you are “doing it right.” By week two to three of your keto diet, your glycogen stores will be gone and you’ll start burning through body fat.

Here’s how:

  • Your low carbohydrate and high-fat diet results in low blood sugar levels.
  • Low blood sugar levels in your body reduce insulin levels – insulin is the hormones that allow sugar into the blood cells.
  • Low production of sugar that is usually influenced by insulin results in the burning of fats and more production of the ketone.

As you continue to burn fat on your keto diet, your weight loss is sustained. Even if your weight loss seems to have reduced, keep in mind that first, you lose water weight before the fat starts to burn.



Another way to know that you are in ketosis is during the initial stages. Headaches can be a common side effect of switching to a Ketogenic diet. They may happen as a result of consuming less carbohydrates than usual. 

The dehydration that comes with newly starting the keto diet and electrolyte imbalances can also be a cause of the headaches that accompany newly starting a low-carbohydrate diet. These headaches usually do not last for too long, they should only last from about day one of starting on the diet, to about the end of the first week.

Headaches should relief fast. Some researchers have proven that the keto diet could be a possible treatment for individuals with chronic and or episodic migraine. Di Lorenzo et al., (2018) work shows a dramatic reduction in participants’ migraines after being introduced to the keto diet.

Although, headaches might occur in the first few days of being in ketosis, but should be resolved within a few days.

Reduction in Appetite


Your body is adjusting to a new lifestyle that excludes something you’re (probably) used to- carbohydrates. You’ll notice a significant drop in your appetite once you go on keto, this is one of the most apparent signs that your body is in ketosis. 

Some of the many reasons you might lose appetite on keto include Higher fat intake, low blood sugar, and rising ketone levels. You might also experience a reduction in appetite due to ingesting a lot of liquids in order to stay hydrated; this makes you more full and wanting to eat less.

On Keto diet, your body is also producing more of a hormonal substance called Cholecystokinin (CCK). CCK is responsible for making you feel full. The more full your body feels, the less you are going to want to eat. When you do not feel hungry, you will find yourself going without food or even cravings for several hours; this can, not only help your weight loss goal, it also shows that you are most likely in ketosis.

Digestive Issues


Another common symptom that accompanies ketosis is digestion issues such as constipation, diarrhea, and stomach aches.

Like fatigue and tiredness, these symptoms won’t last forever. They are usually due to the sudden change in diet, electrolyte imbalances, and change in macronutrient ratios. New dieters are likely to experience these symptoms more than long-term dieters; because you have suddenly (and maybe drastically) cut back on carbs and ingesting more fat than your body is used to, constipation and diarrhea is likely a result. 

Another explanation for digestion issues is the elevated ketone levels in your body. Sumithran et al., confirmed this in their study on “Ketosis and appetite-mediating nutrients and hormones.” The authors asserted that your hunger hormone changes when you get on the keto diet, due to the elevated levels of the ketone. 

Specifically, ketosis suppresses ghrelin (the hunger hormone) release. This is directly or indirectly helpful for your weight loss goal. If your goal is not to lose weight and you desperately want to be able to eat more, give it a few weeks, your body will adjust to the change and develop enzymes that is needed to break down and digest fat, so you’d be able to eat more and maintain your current weight.

Increased Ketones


The most definite way to know that your body is in ketosis is by getting tested. Getting tested for ketones is even more convenient these days as you can easily find a home urine indicator strip kits unlike the traditional method of getting your blood drawn. 

Your doctor could take a sample of your blood and get it tested. Nutritional ketosis would have been reached when your blood ketone level is at 0.5 to 3 millimoles per liter. 

Another way to test ketone levels and find out if your body is on ketosis is to use a breath analyzer to test for ketone in your breath.


Starting the keto diet will result in a change in your way of life almost completely. Although there might be some challenges when newly starting this diet, you can trust your body to adapt to your new lifestyle. Side effects and symptoms of ketosis may also vary widely across individuals.

If you are unsure that you’re in ketosis, you can opt for the Ketone testing using the home kit or from your doctor through a blood sample. Usually, dieters are able to get their body to Ketosis after cutting out carbs and going on their very-low-carb and high-fat diet within a week or two of starting.

  • Di Lorenzo, C., Coppola, G., Di Lenola, D., Evangelista, M., Sirianni, G., Rossi, P., … Pierelli, F. (2018). Efficacy of Modified Atkins Ketogenic Diet in Chronic Cluster Headache: An Open-Label, Single-Arm, Clinical Trial. Frontiers in neurology, 9, 64. doi:10.3389/fneur.2018.00064
  • Frey, S., Geffroy, G., Desquiret-Dumas, V., Gueguen, N., Bris, C., Belal, S., . . . Procaccio, V. (2017). The addition of ketone bodies alleviates mitochondrial dysfunction by restoring complex I assembly in a MELAS cellular model. Biochimica Et Biophysica Acta (BBA) – Molecular Basis of Disease, 1863(1), 284-291. doi:10.1016/j.bbadis.2016.10.028 
  • Hallböök, T., Ji, S., Maudsley, S., & Martin, B. (2012). The effects of the ketogenic diet on behavior and cognition. Epilepsy research, 100(3), 304–309. doi:10.1016/j.eplepsyres.2011.04.017
  • Leonard, J. (n.d.). Signs of ketosis: How to tell if the ketogenic diet is working. Retrieved from 
  • Sumithran, P., Prendergast, L. A., Delbridge, E., Purcell, K., Shulkes, A., Kriketos, A., & Proietto, J. (2013). Ketosis and appetite-mediating nutrients and hormones after weight loss. European Journal of Clinical Nutrition, 67(7), 759-764. doi:10.1038/ejcn.2013.90 
  • Van Berkel, A. A., IJff, D. M., & Verkuyl, J. M. (2018, August 31). Cognitive benefits of the ketogenic diet in patients with epilepsy: A systematic overview. Epilepsy & Behavior, 87, 69–77. Retrieved