Ketosis: Symptoms, Benefits, and Safety

What Is Ketosis Featured Image

Ketosis results in high levels of ketones. This happens when you reduce dietary carbs, a fuel source for most people worldwide. During ketosis, your body uses stored fats as an alternative fuel.

This article defines ketosis, symptoms to note, how it differs from ketoacidosis, its health benefits, and safety concerns.

What is Ketosis?

Ketosis is a natural metabolic state in which your body produces ketones. Ketones or “ketone bodies” are chemicals that are made by your liver when glucose is limited. Your ketone bodies include acetoacetate (AcAc), beta-hydroxybutyrate (BHB), and acetone (Ace) (1)(2).

This natural state is achieved by following ketogenic diets. Thus, it is termed as “nutritional ketosis”. Note that ketosis can also happen when an individual fasts or experiences starvation.

The same process applies in these situations: Low carb availability decreases blood sugar levels and leads to low insulin levels. This triggers ketone production via the metabolism of body fat stores.

Nutritional ketosis ranges from 0.5 mmol/L to 3.0 mmol/L. You can test for ketones using a blood ketone meter, urine strip, or ketone breath meter.

Ketosis Symptoms

Ketosis signs and symptoms can both be positive or negative. Either way, they indicate that the diet is taking effect. Keep in mind that negative keto side effects are temporary and will subside as soon as your body adapts to its new fuel.

Watch out for:

  • Increased ketone levels
  • Keto breath
  • Weight loss
  • Short-term fatigue
  • Thirst
  • Headaches
  • Muscle cramps
  • Insomnia
  • Digestive issues

Ketosis vs. Ketoacidosis

Ketosis and ketoacidosis are metabolic states that sound alike but are different in many ways.

For instance, ketosis is normal and desirable. On the other hand, ketoacidosis is a medical emergency and often a complication of poorly managed Type 1 Diabetes.

Ketoacidosis is characterized by very high ketone levels, making the blood acidic. In this case, ketone levels are 3 to 5 times higher than typical ketosis levels.

This happens in patients with Type 1 Diabetes who may have missed their insulin therapy, experienced an illness, or experienced too much physical stress. Thus, the term “diabetic ketoacidosis.” Other factors that lead to ketoacidosis include alcoholism and malnutrition (3).

Watch out for common ketoacidosis symptoms such as high blood sugar levels, unusually high ketone levels, dry or flushed skin, confusion, and a sweet and fruity odor in your breath.

Ketosis Health Benefits

Nutritional ketosis can be an effective tool for improving health and avoiding disease. Here are some of its benefits you should know about:

1. Ketosis can promote fat loss

Fat loss is a common effect of ketosis. Here’s why that happens:

Decreasing carbs depletes glycogen which causes your body to burn stored fat. Many people find that they lose weight quickly within days of doing keto. But take note, however, that initial “water weight” loss occurs. That’s because glycogen is stored with water in your muscles.

As you sustain the diet, your body becomes more efficient in using its stored fat.

2. Ketosis can help reverse type 2 Diabetes

Virta Health defines reversal as (4):

  • HbA1c below 6.5% (this reading refers to your average blood sugar level over the past 3 months)
  • Elimination of all your diabetes medications (except for metformin)

Virta Health conducted a 2-year non-randomized clinical trial on individuals with type 2 diabetes.

Using nutritional ketosis, participants were able to achieve blood glucose control. It reduced their fasting blood sugar levels, insulin, blood pressure, triglycerides, and improved other health markers (5).

3. Ketosis can improve mental clarity

Eating too much sugar often leads to poor focus. This may explain why after eating a carb-heavy meal, you feel sluggish.

Many people on a keto diet find that they’re able to think more clearly.

But remember: Mental clarity doesn’t come right away. During your body’s transition from a standard American diet (SAD) to a keto diet, you will experience short-term brain fog.

4. Ketosis can improve brain health

Nutritional ketosis may benefit the brain, according to studies:

  • In one study, it was observed that a keto diet improves memory in Alzheimer’s disease patients (6).
  • The diet has been identified as a potential therapy to help traumatic brain injury patients recover (7).
  • 7 people who had Parkinson’s disease followed the keto diet for a month. Their test scores showed improvement (8).

5. Ketosis can help with PCOS in women

The diet improves polycystic ovary syndrome (PCOS) by reducing weight and normalizing insulin. It reduces inflammation in the body, improving a woman’s fertility.

Is Ketosis Safe?

Ketosis is safe in general when achieved using a proper keto diet and with the supervision of a health professional. As more studies are being conducted on nutritional ketosis, we’re seeing how it benefits certain health conditions.

Some people are also concerned that ketosis may lead to ketoacidosis.

Although both differ from one another, a ketogenic lifestyle can cause ketones to reach abnormally high levels in poorly managed diabetes. It can also happen in lactating or breastfeeding mothers who don’t eat enough or starve themselves (9).

The Bottom Line

Limiting your carbs to 20-50 grams per day puts you in a ketotic state. While you reduce your carbs, you also need to increase your dietary fat and keep protein moderate.

Many people turn to this low-carb high-fat diet for its effect on weight loss. Beyond weight loss, keto offers health benefits including mental clarity, reduced inflammation, and better physical performance.

Lastly, keep in mind that ketosis is a normal metabolic state. Ketoacidosis is dangerous, and it often happens in uncontrolled type 1 diabetes. There shouldn’t be any risk in following the diet if you’re doing it properly and with the guidance of a health professional. This is especially applicable to those with medical conditions.


  • Manninen A. Metabolic Effects of the Very-Low-Carbohydrate Diets: Misunderstood “Villains” of Human Metabolism. 2004 December 31
  • Laffel L. Ketone bodies: a review of physiology, pathophysiology and application of monitoring to diabetes. 1999 November-December
  • Fedorovich S, Voronina P, Waseem T. Ketogenic diet versus ketoacidosis: what determines the influence of ketone bodies on neurons? 2018 December
  • Virta Health. Reversing Type 2 Diabetes: An Evidence-Based Guide
  • Athinarayanan S, Adams R, Hallberg S et al. Long-Term Effects of a Novel Continuous Remote Care Intervention Including Nutritional Ketosis for the Management of Type 2 Diabetes: A 2-Year Non-randomized Clinical Trial. 2019 June 05
  • Rusek M, Pluta R, Ułamek-Kozioł M et al. Ketogenic Diet in Alzheimer’s Disease. 2019 August 09
  • McDougall A, Bayley M, Munce S. The ketogenic diet as a treatment for traumatic brain injury: a scoping review. 2018 January 23
  • The Charlie Foundation. Studies Show Efficacy of Keto for Parkinson’s.
  • Nnodum B, Oduah E, Albert D et al. Ketogenic Diet-Induced Severe Ketoacidosis in a Lactating Woman: A Case Report and Review of the Literature. 2019 July 08
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Tiffany Joy Yamut, RN
Tiffany Joy Yamut, RN
Tiffany Joy Yamut is a registered nurse and author of hundreds of health and nutrition articles focused on the ketogenic diet. She discovered the keto diet in 2019, which helped her lose 44 pounds and achieve healing. She’s been featured in Perfect Keto, Ketogenic, Kiss My Keto, and other top health and wellness websites. Follow her on Twitter and LinkedIn.
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Evidence based

This article is based on scientific evidence, written and reviewed by experts.

The founders of Ketogenic Buddies are health care professionals. As we grow, we include other qualified subject matter experts as part of our content team.

This article contains scientific references. The numbers in the parentheses (1, 2, 3) are clickable links to peer-reviewed scientific papers.