1- What is Ketosis?
Ketosis is a metabolic state characterised by your body using fat and ketones as its main source of fuel rather than glucose (sugar).
Your liver is responsible for storing glucose and releasing it as needed for energy. However, when your carb intake drops to extremely low levels for a couple of days, your glucose stores will be depleted. Even though your liver can still make some glucose from amino acids found in the protein you eat (using a process called gluconeogenesis), that is not nearly enough to support your brain, which is the most energy hungry organ in the body.
The body then needs to search for an alternative source of energy. Enter fat and ketones!
Most organs in your body will be able to use fat directly as a source of energy, but not the brain. The brain can only run on glucose or ketones. Since we have restricted glucose, ketones are the answer.
When in ketosis, your body will accelerate the production of ketones. Ketones are produced by your liver from the fat you ingest and your own body fat. There are three ketone bodies: beta-hydroxybutyrate (BHB), acetoacetate and acetone.
Note that your liver is always producing ketones, even when you are in a higher carb diet. The ketones produced are done mostly at night while you sleep and in tiny amounts. When you enter ketosis, your liver will gear up the ketone production in order to supply your brain with energy.
When the amount of ketones in your body reaches a certain level, you are considered to be in nutritional ketosis. The minimum threshold for nutritional ketosis is generally considered to be 0.5 mmol/L of BHB (the ketone body found in your blood).
While both fasting and the keto diet will enable you to reach ketosis, only a keto diet is sustainable over the long term. In fact it seems to be a healthy way of eating that can be followed indefinitely. (1) (2) (3) (4)
Are carbs essential for the brain?
For a long time people have believed that carbs are necessary for proper brain function. This belief is, however, misguided.
In evolutionary terms, our brain is one of the greatest developments of our kind and it has set humans apart from other mammals. However such an extraordinary organ could only thrive in an environment where there was enough energy to sustain it, and in prehistoric times, humans did not have access to processed flours or sugar. In fact, the body evolved in such a way that it had to be prepared for no food intake for extended periods of time, and the brain had to be able to function under those conditions.
It is true that the brain requires some glucose to support its functioning, but when you’re in ketosis it will have abundant fuel source in the form of ketones and will rely predominantly on them. For the small amount of glucose necessary, the brain is supplied by the liver, which is constantly producing glucose, even when you are in starvation mode. (5)
The truth is that being in ketosis not only does not negatively affect your brain performance but in fact does quite the opposite. Ketones are the preferred fuel of the brain. Many people find that they feel much sharper, alert and responsive when their brains run on ketones. This is one of the great benefits of the keto diet and is particularly helpful to people suffering from ADHD.
The small amount of glucose needed by other parts of the body (such as red blood cells and kidneys) can easily be supplied even with a keto level carb intake and/or gluconeogenesis. All other structures in the body can run on either fat or ketones.
2- Benefits of being in ketosis
Beyond being a sustainable energy source, ketones may help reduce oxidative stress and inflammation in the body, which are believed to contribute to many chronic diseases and the aging process. (6)
There are several know benefits of being in nutritional ketosis:
Appetite reduction: One noticeable outcome of achieving ketosis felt by anyone doing the keto diet is the fact that they’re no longer hungry all the time. Research shows that being in ketosis suppresses the appetite. (7) Studies have shown that people following a ketogenic diet have lower levels of ghrelin (the “hunger hormone”) when compared to people who are not in ketosis. (8)
Weight loss: Most people naturally eat less when restricting carbs and allowing themselves to have as much fat and protein as required to make them feel satisfied. There is a triple effect of reduction in appetite, decrease in insulin levels and increased fat burning that leads the ketogenic diet to outperform other diets intended for weight loss. (9) (10)
Combating diabetes: People with type 2 diabetes or prediabetes may see their blood sugar levels and insulin response normalising, which could lead to discontinuation of diabetes medication. (11)
Possibly increased athletic performance: Ketosis may be a source of long-lasting energy supply during sustained exercise in both top performing and hobby athletes. (12)
3- Nutritional Ketosis is not Ketoacidosis
Nutritional ketosis and diabetic ketoacidosis are completely different conditions. While nutritional ketosis is safe and beneficial to health, ketoacidosis is a potentially deadly medical issue.
Unfortunately the difference between the two is still widely misunderstood.
Ketoacidosis mostly occurs in people with type 1 diabetes if, for some reason, they do not take insulin. In this condition, blood sugar and ketones increase to dangerous levels, disrupting the blood’s delicate acid-base balance. This causes people suffering from ketoacidosis to feel extremely ill and experience acute dehydration, abdominal pain, vomiting and weakness. Diabetic ketoacidosis (DKA) requires the person to be hospitalized so that insulin and IV fluids can be administered to gradually lower blood sugar.
While in diabetic ketoacidosis BHB levels can often reach 10 mmol/L or above (directly related to their inability to produce insulin), in nutritional ketosis these values will typically remain below 5 mmol/L.
When the ketone production rises above a certain level, the pancreas of a healthy person will release enough insulin to shut down the ketone production. In a person with type 1 diabetes this does not happen, so unless insulin is administered via injection or IV, ketones will continue rising to dangerous levels.
In some rare cases, women who do not have diabetes can develop ketoacidosis while breastfeeding.
However, for most people not suffering from diabetes, it’s nearly impossible to go into ketoacidosis.
4- Tips for getting into ketosis
- Consume less than 20 grams of net carbs per day: Some people might be able to get away with consuming less than 50 grams of net carbs per day, however consuming less than 20 grams guarantees you will achieve nutritional ketosis. To find out what 20 grams of carbs look like check our keto recipes <link to recipes> and meal plans <link to meal plans> that restrict carbs to less than 20 grams per day.
- Intermittent fasting: Fasting is one of the most effective ways to put your body into ketosis faster. Try going for 16 to 20 hours without eating in a day. This is easy to achieve if you simply skip breakfast or dinner. Remember that during sleep you are also fasting. <link to intermittent fasting blog post – to be produced>
- Eat fat: As most of us have grown up in a world conditioning us to avoid fat, this can be an uneasy task. Throw away the old preconceptions and indulge in the most delicious part of doing a keto diet. Eating plenty of fat is a necessary part of the keto diet. Make sure to include food containing healthy fat in each meal <link to healthy fat article – to be produced>
- Use coconut oil when cooking: Coconut oil has some important benefits. It is a natural fat that remains stable at high temperatures, making it safe to cook with. Additionally, coconut oil is rich in medium-chain fatty acids that help to boost ketone production and may also help maintain brain health. (15)
- Exercise: Perhaps in the early stages of achieving ketosis you might not feel like you have the energy for vigorous exercise, however, a simple power walk might help you achieve ketosis faster.
5- Protein and ketosis
Many people undertaking the ketogenic diet tend to abuse protein intake to compensate for the lack of carbs. In part this happens because during daily life, when eating out, the most abundant source of calories tend to come from carbohydrates, followed by protein. Decades of misinformation with regards to fat led to a relative scarcity of snack options, which are high in healthy fats, without a corresponding elevated load of carbs. Because of this, many people turn to consuming more protein.
Note that the keto diet is a high-fat, medium-protein, low-carb diet. During digestion, protein will be broken down into individual amino acids, which will trigger the release of insulin. This insulin is used to transport these amino acids into the muscles, however only a small quantity of insulin is required to perform this task.
When large quantities of protein are ingested, the rise in insulin levels may somewhat reduce the production of ketones.
However this effect seems to vary considerably from person to person. Some people will notice that a modest increase in protein consumption will promptly lower the level of ketones in their blood stream, while others will see no material difference as long as carb intake is below 20 grams per day.
Keep an eye out for how protein affects your ketone levels and adjust intake accordingly.
6- What is the optimal level of ketosis?
There is a broad range for nutritional ketosis as illustrated below.
While nutritional ketosis will begin at BHB levels of 0.5 mmol/L, it is believed that the optimal ketone zone of 1.5-3.0 mmol/L reflects maximum fat burning. These levels may be temporarily boosted by exercise but should revert to the optimal range.
Some people may observe sustained levels of ketones above 3.0 mmol/L, but these are usually seen in starvation ketosis, which generally occurs when fasting. Note that there is no evidence that BHB levels above 3.0 mmol/L provide any additional benefit to weight loss or diabetes compared to staying within the optimal range.
Ketone levels in your blood above 10 mmol/L indicate ketoacidosis, which is a potentially deadly medical emergency requiring immediate hospitalization.
Note that while BHB levels between 1.5-3.0 mmol/L are considered optimal, they are not strictly necessary for blood sugar control and weight loss. It has been demonstrated that people are able to have very good results even in lower ranges of nutritional ketosis.
7- How do I know I am in ketosis?
The sure way to know if you are in ketosis is to measure your ketone level. However there are some telltale signs that can give you a hint that you are in ketosis. These include:
- Metallic taste in the mouth
- Increased thirst.
- More frequent urination.
- Dry mouth.
- “Bad” breath.
- Initial tiredness followed by increased energy.
- Lowered appetite and food consumption.
There are generally three ways to measure your ketone level: blood, breath and urine. Measuring ketones in the blood is the most accurate way to know if you are in ketosis, followed by breath and urine. A good tip is to measure your ketone levels late morning or afternoon, as blood and urine ketones are usually at their lowest immediately after waking up.
There are many metres in the market for measuring BHB levels in your blood. The measurement scale for nutritional ketosis is as follows:
Mild ketosis: 0.5-1.0 mmol/L
Moderate ketosis: 1.0-1.5 mmol/L
Optimal ketosis: 1.5-3.0 mmol/L
There are analysers in the market that will measure the amount of acetone in your breath using a color-coded system. Check within each product to know the colour correspondence.
Urine testing is done with the use of urine strips, which will measure the amount of acetoacetate that is excreted in the urine. Any shade between light pink and purple indicate that you are in ketosis. The darker the colour, the deeper into ketosis you are.
However note that this method of measurement may be misleading. If you are dehydrated, the urine strip will also turn dark and that does not necessarily mean you are in ketosis. Also, usually measuring ketones in the urine works best when you are first entering ketosis, as later on, urine acetoacetate levels in the urine may decrease.