GET $10, GIVE $10
Give your friends $10 off on their first order of $50+ and get $10 in points for each successful referral.
Get $10 Now


Is Ketosis Safe? What Research Says

Published on: August 17, 2019

Is Ketosis Safe? What Research Says

Previous Article: What Are the Health and Metabolic Benefits of Ketosis

Main Page (Index): Ketosis: The Complete Guide

Next Article: An In-Depth Look at The Ketosis Metabolism: What Happens Inside Your Body

Adhering to a low-carb, high-fat diet can seem tough when you hear stories about the dangers and risks of ketosis. But really, is ketosis safe?Today, we’re going to explore the safety of nutritional ketosis from a scientific perspective.

Without further ado, let’s dive in.

How Long Is It Safe to Be in Ketosis?

You can be in ketosis for as long as you want by continuously maintaining increased ketone levels. Let’s recall that to get into nutritional ketosis, you need significantly decrease your dietary carbohydrates to below 50 grams and eat a moderate amount of protein [1].

While the number of studies conducted on long-term ketosis is limited, we’re going to tackle the ones that are available. Below, you’ll discover how people with health conditions were able to maintain a keto diet for several weeks to years without consequences:

24 weeks

83 obese patients, which consisted of 39 men and 44 women, were put on a ketogenic diet for 24 weeks. They consumed 20g to 30g of carbohydrates, 80g to 100g of protein, and polyunsaturated and monounsaturated fats. They were also given one capsule of vitamins and minerals each day [2].

Data showed that the patients’ weight decreased significantly as well as their BMI. Their blood glucose, total cholesterol, and LDL levels decreased. Their HDL cholesterol level significantly increased. Results from the study indicated that following a keto diet long-term is safe [2].


2 years

Virta Health conducted a 2-year non-randomized controlled study on the effects of nutritional ketosis on patients with Type 2 Diabetes [3].

During the first year, the researchers noted an improvement in weight, glycemic outcomes, lipid markers, and liver markers among the participants. During the second year, they noted a reduction of HbA1c, fasting glucose, fasting insulin, weight, systolic blood pressure, diastolic blood pressure, triglycerides, and liver alanine transaminase among the patients. What’s interesting was that nutritional ketosis improved the patients’ health markers without adversely affecting their bone health [3].

Over 5 years

A study was conducted to explore whether the keto diet negatively impacts the bone health status of Glut1 Deficiency Syndrome patients who received the diet as a principal treatment [4].

Results revealed that maintaining a keto diet for over 5 years does not lower the bone mineral content, bone mineral density, and body composition of adults with Glut1 Deficiency Syndrome [4].

People find themselves switching into and out of ketosis

However, staying in ketosis indefinitely or for the rest of your life is not something that a lot of people look forward to. In fact, most individuals find it harder to maintain a ketotic state (especially deep ketosis) than to achieve it.

Usually, people end up moving in and out of ketosis for various reasons. For example, they want to enjoy an extended family celebration without having to track their carbs or load up on carbs once a week.

Is Ketosis Bad?

You already know that you can do ketosis long-term.

But some people still wonder if it’s bad.

Here’s why:

They confuse ketosis with ketoacidosis.

Ketoacidosis rarely happens in healthy individuals. Rather, it’s a serious complication among diabetics who often miss insulin treatments. In ketoacidosis, a person’s ketone levels become abnormally high. They can exceed concentrations of 20 mmol/L.

As you can see, this is a much higher value than nutritional ketosis. (In nutritional ketosis, ketone levels remain between 0.5–3.0 mmol/L.)

So, to answer your question:

Ketosis is not bad. It gets your metabolism into a fat-burning mode. That means your body uses fat for fuel.

Ketosis also helps you build metabolic flexibility. When you’re metabolically flexible, your body uses whatever fuel is available.

Another reason why ketosis is good is that your extrahepatic tissues can use ketones. These organs include your brain, heart, and skeletal muscles. Some disease states also benefit from ketosis. A few examples are epilepsy, diabetes, cancer, obesity, and Alzheimer’s.


Is Ketosis Safe for Everyone?

Ketosis through a well-formulated ketogenic diet is safe for most people.

To explain why ketosis is a safe metabolic state that you want to be in, we’re going to address common areas of concern such as: how ketones compare to glucose as a fuel source, the risk of eliminating carbohydrates from the diet, and more.

What it means to run on ketones for fuel

When you’re in a ketotic state, it means that ketone bodies have replaced glucose as your energy source. Ketone bodies can be readily utilized by your heart, muscles, kidneys, and brain [5].

In fact, ketone bodies are considered a “super fuel” due to the fact that they produce much more ATP than glucose. 100 grams of glucose can only produce 8,700 grams of ATP while the same amount of beta-hydroxybutyrate (BHB) produces 10,500 grams of ATP. That said, ketones can keep you going for longer even during periods of starvation [5].

The major ketone body BHB benefits the body in several ways. It reduces inflammation by inhibiting the NLRP3 inflammasome (a protein responsible for activating inflammatory processes). It also boosts your weight management efforts by influencing your appetite and satiety [6, 7].

Despite these benefits of using ketones for fuel, ketones still get a bad rap.

The reason for this is that ketones were first discovered during the mid-19th century in the urine of patients with uncontrolled diabetes. Because of that, they have been associated with metabolic dysfunction for 150 years. It was in 1967 when it was discovered that ketones can replace glucose as the brain’s major fuel [8, 9]

What it means to run on glucose for fuel

People on a Western diet are “sugar burners” since they derive their energy from carbohydrates. Western diets contain about 200-300 grams of carbohydrates daily [10].

Utilizing dietary carbs, especially simple carbs, as your main fuel source leads to frequent cravings, hunger, and the feeling of tiredness since they raise your blood glucose and insulin [11, 12].

Studies also show that increasing your intake of dietary sugars predisposes you to weight gain and obesity, diabetes, metabolic syndrome, heart disease, and dementia [13].

There is no evidence of carbohydrate deficiency in humans. Controlled laboratory studies show that elimination of dietary carbohydrates causes no problems unless combined with glycerol restriction (glycerol is obtained from fat) [14].


The risk of eliminating carbs from the diet

Cutting out carbohydrates from your diet puts you at risk for vitamin and mineral deficiencies, leading to health problems [14].

Those following a ketogenic diet should focus on meeting their micronutrient needs such as sodium, potassium, calcium, magnesium, and B-vitamins. Make sure that you take supplements or eat foods that are nutrient-dense and low in carbs.

A well-formulated keto diet is essential

Unpleasant ketosis side effects and adverse effects usually happen as a result of a poorly formulated ketogenic diet. Those who try to navigate nutritional ketosis on their own without adequate knowledge and guidance from a health professional will fail to get the best results from it [15].

Dr. Steven Phinney, Dr. Brooke Bailey, and Dr. Jeff Volek outline the characteristics of a well-formulated keto diet. These characteristics include but are not limited to the following [15]:

  • Nutritional ketosis should be sustained. This entails a beta-hydroxybutyrate (BHB) concentration of 0.5 mM and 4.0 mM. Variety and taste are also necessary for a person to be able to sustain a keto diet.
  • A person should maintain a moderate protein intake, keeping it between 1.2 g to 2.0 g per kg of body weight.
  • There should be enough electrolytes and minerals to prevent adrenal stress, muscle cramps, and also to preserve lean body mass regardless of the protein intake.
  • Your daily energy source should come mostly from dietary fat.


Getting medical supervision for certain conditions

Individuals with conditions that require blood sugar and blood pressure medications, such as diabetes and hypertension, should seek medical supervision prior to following a ketogenic diet.

This is because following the keto diet inevitably decreases blood glucose levels [16, 17]. Lowering your glucose and insulin can also lower your blood pressure [18, 19].

A physician who understands ketosis and knows how to leverage it can make adjustments to your medications to avoid drastic reductions in your blood glucose or blood pressure.


Ketosis is considered to be safe for most people as long as professional guidance is sought and a well-formulated ketogenic diet is followed.

It’s easy for one to be completely against nutritional ketosis without getting into the science of this natural metabolic state. Hopefully, this guide was able to straighten out some of the confusion surrounding ketosis.

While studies show that nutritional ketosis can be sustained without major consequences for weeks to years, many people, in general, find indefinite ketosis less of a priority and would rather cycle in and out of keto.


  • Ketones are a “clean fuel” and serve as a much more efficient energy source than glucose.
  • Increasing your ketone levels puts you in ketosis, which offers you a ton of health benefits from decreased inflammation to an increase in satiety.
  • Being outside of ketosis while following a standard Western diet that’s high in sugar and carbohydrates puts you at risk for several diseases.
  • Adverse events in ketosis are usually the consequence of not following a properly formulated keto diet.
  • Eating fewer carbohydrates is not enough to keep nutritional ketosis risk-free; one should seek medical supervision, pay attention to his macro and micronutrient intake, and more.


  1. Phinney S, Virta Team. How do I get into nutritional ketosis?
  2. Dashti HM et al. Long-term effects of a ketogenic diet in obese patients. 2004 -
  3. Athinarayanan SJ et al. Long-Term Effects of a Novel Continuous Remote... View all references

Join Over 200,000 Fans

Sign up for the Kiss My Keto mailing list to get free keto resources, recipes, and strategies from the largest keto brand in the world.