Ketosis Symptoms and Signs: What to Look Out For

Image of graph of blood bhb levels with human in the background

It can be hard work to follow the ketogenic diet or fast to get into ketosis. By contrast, it's easy to raise blood ketone levels and get into ketosis by taking exogenous ketones like HVMN Ketone. But how do you know you are in ketosis? What are the positive signs and what about the negative symptoms you might have to deal with? 

Recap on Ketosis

Ketosis is a normal metabolic state marked by higher-than-normal levels of ketones (or ketone bodies) in the blood. This can happen as a result of endogenous ketone production in the body or after consuming exogenous ketones. Endogenous ketosis is the body’s natural adjustment to the absence or restriction of carbohydrate in the diet. Without enough glucose from carbs to fuel  its cells, the body turns to fat to replace glucose as its primary source of energy.  In the liver, fat that is not burned for energy directly is converted to ketones. This means that you are in a ketogenic state. Ketone levels increase in the bloodstream and provide an alternate and efficient fuel source for the body and brain. As a result, muscle protein is spared from being converted to glucose for energy.

With exogenous ketones, you consume a ketone drink containing a ketone ester or a ketone salt and this raises blood ketone levels. The ketones have come from the drink, so you are not in a fat-burning ketogenic state, but technically speaking you are in ketosis and able to use ketones like betahydroxybutyrate for energy.

So how do you know you are in ketosis?

Measuring Ketosis

Blood ketone monitor kit to measure ketone levels

An increase of ketones in the breath, blood, and urine is the best sign of ketosis. Seeing blood ketone levels have changed by measuring your own biomarkers is very empowering! Measuring ketone levels in the blood is the most accurate way to know for sure. A blood ketone level of 0.5 mmol/L is widely acknowledged as the threshold for entering ketosis.1 Blood testing is reliable for quantifying both endogenous (created by ketogenic diet, fasting, exercise) ketones and exogenous ketones such as HVMN Ketone. Urine and breath measurements are less reliable but can be useful as quick, noninvasive ways to  approximate blood ketone levels.2 

Unwanted Symptoms of a Ketogenic Diet

While prolonged or strenuous exercise, fasting, and exogenous ketones can also significantly raise blood ketones, the ketogenic diet remains the most common approach to trigger a state of ketosis. The ketogenic diet is low in carbs with low/moderate protein and high in fat. Carbohydrates are typically reduced to less than 50 grams/day. Carbohydrate reduction results in a ketogenic state; ketosis occurs as a result of  the body becoming ketogenic.

Apart from biomarker  testing, subjective symptoms can be a good guide that you are in ketosis. The early stages of the ketogenic diet are sometimes associated with mild side effects related to withdrawal of carbohydrates. These symptoms, often referred to as “keto flu,” include nausea, fatigue, headache, and dry mouth. They are short-term, typically lasting about a week or less. Keep in mind, however, that we are all different. Our bodies react in different ways. Some of us may experience these symptoms later than sooner, to a lesser extent, or not at all.

Other symptoms linked to the ketogenic diet include:

Gut Issues: Frequent Urination, Constipation, Diarrhea  

Glycogen is the body’s storage form of carbohydrate energy and is found primarily in liver and muscle cells. Each gram of glycogen is bound with 3 to 4 grams of water.3 On a low-carb diet, the body will burn through these glycogen stores, releasing a lot of water and causing frequent urination. As insulin levels drop from drastically cutting carbs, more water is flushed out, along with excess sodium (in contrast, excess insulin from excess carbs causes sodium and water retention.4  In some people, dehydration contributes to constipation, which can also result from avoiding fiber-rich carbohydrate foods. While less common, diarrhea or loose bowels can be triggered by a number of factors including too much or too little fat, dairy intolerance, or changes in gut flora. 

Many people on the ketogenic diet never experience gut problems. Those that do can benefit from drinking plenty of water and mineral-rich broths, and eating more non starchy veggies along with foods rich in both fat and fiber, such as nuts, nut butters, and avocado.

Rapid Weight Loss/Long-term Weight Loss

As glycogen stores become depleted and water attached to glycogen is released (as described above), rapid weight loss in the form of “water weight” occurs. Once glycogen stores run out, however, ketosis kick in as body fat is burned. Strong evidence supports the use of ketogenic diets for long-term weight loss. The appetite-suppressant effects of ketosis leading to decreased calorie consumption is considered to be the most plausible mechanism through which the diet works.1 

Bad Breath

Some people complain of bad breath, or ketosis breath, when eating low carb. Acetone, the least abundant ketone, is present in the breath and is responsible for this unpleasant odor. What does it smell like, you ask? (hint: acetone is the solvent in nail polish remover). It’s not all bad though. Acetone breath is a sign of ketosis and fat burning!  It happens to be the ketone that is measured in breath tests used for detecting ketosis.5 In any case, for those who experience ketosis breath, it typically goes away after several weeks on the keto diet. In the meantime, drink more water and use breath fresheners often. You may also consider adding just enough carb back into your diet to avoid bad breath while still staying in the ketosis zone.

Positive Signs You’re in Ketosis

On the flip side, there are many positive effects that you may experience when you achieve a state of ketosis. Some of these are side effects of lowering carbohydrate intake of the diet, but many benefits come from the presence of ketones themselves. This means that there are similarities and differences between may be differences in the benefits you might expect from endogenous ketosis and exogenous ketosis. 

Man working on computer with chalkboard in background

Increased Mental Focus & Decreased Brain Fog

Ketones have pronounced effects on the brain. On a low-carb ketogenic diet, and after exogenous ketone drinks the brain uses ketones as a major fuel source. Beta-hydroxybutyrate, the major ketone, is actually more energy efficient than glucose! It also stimulates production of new mitochondria - the energy factories in our cells.6 It should come as no surprise, then, that increased mental clarity and focus, and less brain fog, are often reported by healthy people in ketosis.  HVMN CEO, Geoffrey Woo is quoted as saying that “after a drink of HVMN Ketone, it’s like I’m more behind my eyeballs,” so it appears that exogenous ketones can subjectively improve mental performance and clarity.  When HVMN Ketone was tested in mice, they performed 38% better on a maze solving challenge, so it is possible that there may be a cognitive boost for humans also.7  When following a ketogenic diet, you avoid the energy peaks and troughs that come from quick-energy carbs. Producing ketones from stored body fat provides the brain with a steady, sustainable supply of fuel. This can result in greater work productivity or performance. In a study in people with mild cognitive impairment, eating a low carbohydrate diet resulted in more mental energy and feeling more clear-headed.

Decreased Appetite

One of the first symptoms you might notice when on a ketogenic diet is that it kills your appetite. People on the diet report being significantly more full and satisfied. Even though you may be ingesting LESS calories on the diet, your hunger is not increased.  One likely explanation is greater consumption of satiating foods, primarily protein and fat. However, multiple studies indicate that the state of ketosis itself (apart from effects from food) plays a role as well.8 High levels of circulating ketones may have a direct appetite-suppressant effect. In fact, the exogenous ketone ester used in HVMN Ketone rapidly increased blood levels of beta-hydroxybutyrate and lowered appetite as well as levels of ghrelin - a hormone that increases hunger. Whilst this still has to be explored further, it is possible that exogenous ketones may be useful for appetite control as part of a holistic weight loss strategy.9

Symptoms of Dangerous Diabetic Ketoacidosis

In nondiabetics, ketosis (also called nutritional ketosis) is regulated and controlled in the body so that ketone levels never reach the harmful levels associated with diabetic ketoacidosis. Ketoacidosis ia an acute, life-threatening condition that occurs in severely uncontrolled diabetes (mainly type 1) when ketones rise to massive, supranormal levels. Since the body’s acid-base buffering system cannot neutralize the vast amount of acidic ketones, the blood pH drops significantly. This buildup of acids in the blood poisons the body and  can lead to ketoacidosis.10 Breathing becomes deep and rapid as the body attempts to compensate for excessive acids. Other symptoms of diabetic ketoacidosis include:

  • Extremely high glucose levels
  • Nausea and vomiting
  • High levels of both glucose and ketones in urine
  • Can lead to a coma

Importantly, this dangerous condition is rare in non-diabetics following a ketogenic diet,  and in people taking exogenous ketones. So long as you stick to the recommended dose of max. 3 drinks per day of HVMN Ketone, there is no risk of ketoacidosis. 

Take Home Message

Ketosis is the body’s normal physiological response to a shortage of carbohydrate fuel. It is characterized by elevated blood levels of ketone bodies, or ketones. Ketosis is a healthy, natural state that should never be confused with ketoacidosis, a dangerous and potentially life-threatening complication of diabetes.

A raised ketone level in the blood is the best sign of ketosis.  Certain subjective symptoms can signal ketosis as well. Increased mental clarity, less brain fog, and diminished appetite are fairly common among people in ketosis. The ketogenic diet has its own assortment of symptoms. Fortunately, the negative symptoms such as constipation, diarrhea, and bad breath are often temporary and tend fade as your body becomes better at fat burning and naturally producing ketones. 

For the most part, the positive symptoms of ketosis coincide with higher levels of ketones in the blood. This may occur after  several weeks of adhering to the ketogenic diet or very shortly after ingesting exogenous ketones.

  1. Paoli, A., Bianco, A., Grimaldi, K.A., Lodi, A., and Bosco, G. (2013). Long term successful weight loss with a combination biphasic ketogenic Mediterranean diet and Mediterranean diet maintenance protocol. Nutrients 5, 5205-17.

  2. Stubbs, B.Cox, P.; Evans, R.; Santer, P.; Miller, J.; Faull, O.; Magor-Elliott, S.; Hiyama, S.; Stirling, M.; Clarke, K. (2017). On the metabolism of exogenous ketones in humans. Front. Physiol.

  3. Olsson, K.-E. and Saltin, B. (1970), Variation in Total Body Water with Muscle Glycogen Changes in Man. Acta Physiologica Scandinavica, 80: 11–18. doi: 10.1111/j.1748-1716.1970.tb04764.x

  4. DeFronzo RA, Cooke CR, Andres R, Faloona GR, Davis PJ. The effect of insulin on renal handling of sodium, potassium, calcium, and phosphate in man. Journal of Clinical Investigation. 1975;55(4):845-855.

  5. Musa-Veloso, K., Likhodii, S.S., and Cunnane, S.C. (2002). Breath acetone is a reliable indicator of ketosis in adults consuming ketogenic meals. Am J Clin Nutr 76, 65-70.

  6. White H, Venkatesh B. Clinical review: Ketones and brain injury. Critical Care. 2011;15(2):219. doi:10.1186/cc10020.

  7. Murray, A.J., Knight, N.S., Cole, M.A., Cochlin, L.E., Carter, E., Tchabanenko, K., Pichulik, T., Gulston, M.K., Atherton, H.J., Schroeder, M.A., et al. (2016). Novel ketone diet enhances physical and cognitive performance. FASEB J.

  8. Gibson, A.A., Seimon, R.V., Lee, C.M., Ayre, J., Franklin, J., Markovic, T.P., Caterson, I.D., and Sainsbury, A. (2015). Do ketogenic diets really suppress appetite? A systematic review and meta-analysis. Obes. Rev. 16, 64-76.

  9. A Ketone Ester Drink Lowers Human Ghrelin and Appetite Stubbs, Brianna J., Cox, Pete J., Evans, Rhys D., Cyranka, Malgorzata, Clarke, Kieran, de Wet, Obesity, November 2017

  10. Manninen AH. Metabolic Effects of the Very-Low-Carbohydrate Diets: Misunderstood “Villains” of Human Metabolism. Journal of the International Society of Sports Nutrition. 2004;1(2):7-11. doi:10.1186/1550-2783-1-2-7.

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