What Is Ketosis?
A basic ketosis definition is an increase of ketones in the body caused by a reduction in carbohydrate intake.5
Today, it’s common to hear people talking about “going into ketosis” to lose weight or manage hunger. As one of the latest movements in the health industry, more and more people are looking to achieve this metabolic state. But what does ketosis mean?
To explain ketosis, we first need to understand ketones.
Ketones are water-soluble molecules produced in the liver. They’re a by-product of the production of glucose (the body’s fuel) from non-carbohydrate sources. In other words, they are produced when the body is short on ready-made fuel.6
Such shortages occur when the body experiences low intake of calories, during extreme exercise, low-carb diets, fasting, or starvation. In some cases, people suffering from alcoholism or poorly treated Type 1 diabetes will have excessive ketone production.6
Ketosis is a normal metabolic process that occurs naturally during short-term periods of fasting, such as sleep. In the body, a small number of ketones are always present in the blood and urine, but are generally undetectable.6
In terms of dieting, ketosis occurs when carbohydrates are severely limited for extended periods of time. The body then turns to stored fatty acids and ketones for fuel.6 This is why it’s popular among people trying to lose weight.
How to Get into Ketosis
If you are looking to lose weight, it’s important to know how to put your body in ketosis without jeopardizing your health.
Fasting will prompt ketosis but is difficult to sustain. Instead, many people follow a ketosis diet. This is a way of eating that severely reduces the intake of carbohydrates. In most cases, carbs make up 5-10% of calories. Protein accounts for 20-30% and the remainder of calories come from healthy fats.
Known for its satiating effect, the healthy fats help minimize hunger and sustain energy levels.1 Switching to a low carb intake triggers ketosis and signals the body to metabolize stored fatty acids into usable glucose. This results in body fat being used as fuel for the body.
For individuals new to ketosis, some of the most common questions include “what happens when your body goes into ketosis?” and “how do you know you’re in ketosis?”
The process of metabolizing fat into glucose produces a few noticeable symptoms of ketosis including:
1. Bad Breath
3. Dry Mouth
4. Frequent Urination
6. Decreased Appetite
1. Ketosis Breath
One of the first signs of ketosis people notice is bad breath. Because it’s produced from within the body and not the mouth, it can’t be brushed away or easily masked.
Often described as “fruity”, ketosis bad breath is caused by acetone, a kind of ketone. The body expels acetone through the breath and urine, leaving both with a distinct aroma.2
2. Ketosis Insomnia and Sleep Troubles
Complex carbohydrates do more than supply the body with glucose, they also facilitate the uptake of L-tryptophan in the brain. If you are severely limiting carbohydrates in your diet, your primary source of L-tryptophan may be eliminated. This may result in difficulty falling or staying asleep.3 For this reason, many people in ketosis report taking L-tryptophan supplements.
3. Ketosis Dry Mouth and Dehydration
As the body loses water during ketosis, dehydration is another frequent symptom. Most people notice dehydration by the dry sensation that occurs in the mouth.
As an easy and important symptom to address, users should ensure they are consuming enough water throughout ketosis. Without ample intake of water, widespread dehydration may occur and cause other health concerns.
4. Frequent Urination from Ketosis
Putting the body in to a state of ketosis may cause the excess release of glycogen. During this process, the water needed to store the glycogen is also released. This is what’s known as “water weight”. This may result in frequent urination, particularly in the beginning stages of ketosis.
5. Ketosis Induced Fatigue
Entering ketosis may leave some individuals feeling listless or fatigued within the first 1-2 days. Often, this symptom is thought of as the body’s defense against starvation, and is a result of the body adapting to the lack of carbohydrates.
The human body is remarkably adaptive and can adjust to being in a continuous state of ketosis. Most people self-report that it takes 7-30 days before normal energy levels return.
One way to help counteract this symptom is to take vitamin B supplements. Involved in both energy production and the metabolism, B vitamins are important for sustain energy levels. Some users have also reported getting vitamin B12 shots as an alternative way to combat short-term fatigue.
6. Decreased Appetite from Ketosis
Increasing research has established a relationship between ketones and hunger hormones. Ketones affect cholecystokinin (CCK), a hormone which indicates to the brain that the stomach is full. It also affects ghrelin, the hormone that signals hunger.5
CCK is released into the intestines after eating. In clinical studies, elevated levels of CCK have been noted to reduce food intake in patients.4 But after weight loss, the body typically releases less CCK. This may leave people feeling less satisfied after a meal. However, when enough calories from fat and protein are consumed in ketosis, CCK levels have been shown to stay at baseline levels.4 The results in users feeling satisfied.
Oppositely, ghrelin is released when blood levels indicate the body is running out of fuel. Within 10-20 minutes of eating, ghrelin levels drop, and hunger dissipates. Low calorie intake and fasting causes the release of ghrelin. But a clinical study showed that during ketosis, ghrelin levels may be reduced.5 This mechanism may also decrease the appetite.
Using Ketosis Strips
Want to know how to tell if you’re in ketosis for sure? Individuals can conveniently use specialized ketosis test strips at home. Available at most pharmacies, the strips are a DIY ketosis test. Treated with sodium nitroprusside, the sticks will change color (anywhere from pink to purple) in response to the concentration of ketones in urine.6
The darker the color, the higher the concentration of ketones in your urine.
How Long Does It Take to Get into Ketosis?
That varies by individual. But anecdotal self-reports say 2-7 days.
Perhaps of greater importance is the question: When does ketosis start? As glycogen stores decrease, the central nervous system begins to look for alternative energy sources, such as ketones. This process may begin 3-4 days after reduced carbohydrate intake.5
From a clinical perspective, ketosis starts when there is a higher than normal level of ketones in the urine.5 Symptoms such as bad breath or reduced appetite may indicate you’ve started ketosis. Individuals can also use ketosis strips to test their urine for increased ketone levels.
How Long Does Ketosis Last?
How long can your body stay in ketosis? Ketosis is a natural mechanism that allows the body to withstand famine. While it is natural, it is not our normal metabolic state.
In theory, your body can stay in ketosis for a very long time. But prolonged ketosis is generally considered unwise in normal circumstances because it can contribute to chronic metabolic imbalances, muscle deterioration, and kidney stones among other condition.7
Difference Between Ketosis and Ketoacidosis
Periods of ketosis are unlikely to harm you. As we’ve discussed, there could even be benefits.
But in rare cases of people with abnormal insulin function, ketosis can lead to ketoacidosis, which is dangerous. Left untreated, ketoacidosis can quickly cause coma or death.8
Symptoms of ketoacidosis include:8
- Extreme muscle weakness
- Abdominal pain
- Shortness of breath
- High blood sugar levels
- Nausea or vomiting
- Severe brain fog or confusion
If you suspect you are in ketoacidosis, seek medical attention right away.
Scientific Research Referenced in this Article
- Blundell, J.E., Stubbs, R.J., Golding, C., Croden, F., Alam, R., Whybrow, J., Le Noury, J., Lawton, C.L. (2005). Resistance and susceptibility to weight gain: Individual variability in response to a high-fat diet. Physiology & Behavior. 86(5). 614-622. https://doi.org/10.1016/j.physbeh.2005.08.052
- Musa-Veloso, K., Likhodii, S.S., Cunnane, S.C. (2002). Breath acetone is a reliable indicator of ketosis in adults consuming ketogenic meals. American Journal of Clinical Nutrition. 76(1). 65-70. https://www.ncbi.nlm.nih.gov/pubmed/12081817
- Hartmann, E. (1982). Effects of L-tryptophan on sleepiness and on sleep. Journal of Psychiatric Research. 17(2). 107-113. http://dx.doi.org/10.1016/0022-3956(82)90012-7
- Chearskul, S., Delbridge, E., Shulkes, A., Proietto, J., Kriketos, A. (2008). Effect of weight loss and ketosis on postprandial cholecystokinin and free fatty acid concentrations. The American Journal of Clinical Nutrition. 87(5). 1238-1246. https://www.ncbi.nlm.nih.gov/pubmed/18469245
- Paoli, A., Bosco, G., Camporesi, E. M., & Mangar, D. (2015). Ketosis, ketogenic diet and food intake control: a complex relationship. Frontiers in Psychology. 6(27). http://doi.org/10.3389/fpsyg.2015.00027
- Comstock, J.P., Garber, A.J., Ketonuria. In: Walker HK, Hall WD, Hurst JW, editors. Clinical Methods: The History, Physical, and Laboratory Examinations. 3rd edition. Boston: Butterworths; 1990. Chapter 140. https://www.ncbi.nlm.nih.gov/books/NBK247/
- Groesbeck, D.k., Bluml, R.M., Kossoff, E.H. (2006). Long-term use of the ketogenic diet in the treatment of epilepsy. Developmental Medicine and Child Neurology. 48(12). 978-981. https://www.ncbi.nlm.nih.gov/pubmed/17109786
- Mayo Clinic. (2015, August 21). Diabetic ketoacidosis. Retrieved December 6, 2017 from – View Reference