What does a ketone level of 3.7 mean?

A ketone reading of 3.7 mM usually means that you are currently experiencing a higher degree of nutritional ketosis.

Nutritional ketosis is a natural metabolic state in which your body is fueled mainly by fats and ketones, instead of carbohydrates (glucose). Nutritional ketosis happens when carbohydrate consumption goes low enough that a person’s liver begins to break down dietary fat and stored body fat into molecules known as ketones, then burn the ketones for energy.

Ketones of 3.7 mM can occur when dietary carbohydrates are significantly reduced (<30 to <50 grams per day) and the body’s production of ketones increases to a blood level at or above 3.7 mM. Some people may experience this level early on in carbohydrate restriction and it is most almost always perfectly safe. Ketones in this range can also be indicative of extended fasting, low protein intake, illness, or dehydration, which will resolve with eating and hydrating. In general, if you feel fine, you are fine.

There are some situations where ketones in this range are concerning, and if you don’t feel well, you should check in with your medical care team. Concerning symptoms include nausea, vomiting, abdominal pain, extreme thirst, frequent urination, headache, and a metallic taste. Very high ketones could be a medical emergency called Diabetic Ketoacidosis (DKA) and should be addressed immediately. DKA usually causes high blood sugar and high ketones. It is most common in people with type 1 diabetes, especially if they get sick or miss their insulin. Some medicines for type 2 diabetes (like Jardiance or Farxiga) can also cause DKA. If you take these, you might still have DKA even if your blood sugar looks normal.

• Increased ketone levels, reading above 0.5 mM
• Decreased hunger and appetite
• Temporary fatigue
• Temporary reduced athletic performance
• Weight loss
• Fruity breath smell
• Temporary sleep disturbances
• Headache

• Sustained ketone levels reading above 0.5 mM
• Decreased hunger and appetite
• Increased physical energy
• Improved cardiovascular athletic performance
• Increased mental focus
• Sustained weight loss
• Improved mood
• Improved sleep

The easiest way to sustain nutritional ketosis is to maintain a well-formulated ketogenic diet. This diet helps your body to use fats instead of carbs for energy, enabling you to utilize ketones as a primary fuel source.

Restricting your carb intake via a ketogenic diet that emphasizes fats over carbs helps you maintain your current state of nutritional ketosis. A well-formulated ketogenic diet includes delicious and healthy fats like butter, avocado, olive oils, fatty meats, and more, along with healthy and nutritious vegetables.

As you continue to restrict carbs below 30 to 50 grams/day and consume a moderate amount of protein, you should normally remain in the ketone level range of 0.5–3.0 mM, which means that you are still in nutritional ketosis. Because it can be helpful to adapt your food preferences and choices to fit within the ketogenic diet, it can be helpful to work with an expert like those at Virta Health to help guide you through the process.

Over time, the body begins to get used to being in nutritional ketosis. When maintained for several consecutive weeks, nutritional ketosis fundamentally changes the way cells in your body work. This includes switching the mix of fuels they use, as well as awakening metabolic pathways that are silenced by high-carb diets. Over time the body refines its metabolism to run on fat and ketones, ultimately manifested by two-fold higher rates of whole-body fatty acid oxidation. Meanwhile, glycolysis, insulin concentrations, constitutive inflammation, and oxidative stress are all decreased. As a result, nutritional ketosis can have prompt and potent therapeutic effects; most notably the reversal of clinical signs of metabolic syndrome and type-2 diabetes. Many other disorders/diseases may be amenable to nutritional ketosis. This is an early-stage but burgeoning area of scientific investigation.