What Should My Ketone Levels Be?

Changing your eating habits can seem like a daunting task, especially on a low-carb, high-fat regimen like the ketogenic diet. Fortunately, once those pounds start melting away, it gets easier!

But unlike other dieting methods, you shouldn’t just track your progress by the shrinking numbers on your scale. You should also keep an eye on your ketone levels to measure your body’s fat-burning progress.

Before we dive into ketones and ketone levels, please note that the following information is not a substitute for professional medical advice. Additionally, if you have conditions such as diabetes, kidney or liver disease, or other serious medical concerns, we highly recommend consulting with your doctor before embarking on a ketogenic journey.

What Are Ketones?

Following a ketogenic diet means swapping the bulk of your carbohydrates for fats. As your body adjusts, you’ll begin to burn fat as your primary source of fuel instead, bringing you into a state of ketosis. ^[1]

During ketosis, your liver breaks down fats for energy and kicks out an acid byproduct known as ketones. You can measure the level of ketones in your blood, breath, and urine in proportion to the amount of fat you’re burning. ^{[2] [3]}

What Should Your Ketone Level Be?

Your ketone levels can vary based on your body, diet, and exercise, among other factors. However, if you take ketosis too far, you may experience potentially dangerous side effects. As such, it’s important to identify the “optimal” level of ketones in your blood.

One of the most commonly cited works on the matter was written by two doctors, Stephen Phinney and Jeff Volek. They suggest in The Art and Science of Low Carbohydrate Living that the ideal ketone level ranges from 0.5 millimoles/liter to 3.0 millimoles/liter. For most people, 0.5 marks the point at which you enter “light nutritional ketosis,” while 1.0-3.0 represents the “optimal” range. ^[4]

Optimizing Ketone Levels for Your Needs

However, where your ketone level should actually be depends on your health and goals.

For instance, if you’re just beginning to integrate the ketogenic diet into your weight loss regimen, you might aim for light nutritional ketosis to begin with. This gives you time to ease into the diet and minimize any potential side effects.

But if you have some medical conditions that can benefit from a ketogenic diet, such as cancer, epilepsy, or a metabolic disorder, aiming for a higher ketone level may provide more therapeutic benefits. Many individuals who regularly fast or follow the ketogenic diet full-time can see ketone levels between 3.0mmol/liter and 5.0mmol/liter. ^[4]

But if you’re going for general health and weight loss, the “optimal” range of up to 1.0-3.0mmol/liter should suit you just fine!

Beware Going Too High!

Bear in mind that it’s possible to raise your ketone levels too much, which can carry serious health consequences.

Typically, ketone levels about 8.0mmol/liter are considered high with negligible benefits toward your ketosis goals. Once you hit 10.0mmol/liter, however, you may experience ketoacidosis.

You may have heard of diabetic ketoacidosis, which is a rare, potentially fatal condition where your insulin is too low, or your ketone bodies are too high. This causes your blood to become too acidic, which leads to symptoms like intense thirst, frequent urination, dry mouth, headache, and fruit-smelling breath. If left untreated, it can even lead to coma or death. ^[6]

While ketoacidosis is most common in patients with diabetes, it’s possible – although rare – to encounter non-diabetic ketoacidosis in patients who strictly follow low-carb, high-fat ketogenic diets. That’s why it’s important to monitor your ketone levels and work with a medical professional if you intend to follow the ketogenic diet long-term – especially if you’re diabetic.

Exercise and Ketone Levels

Many people who follow the ketogenic diet don’t just eat well – they also exercise. While combining a keto diet with proper exercise can help you reach ketosis, it’s important to known how exercise affects your ketone levels.

Studies have found that aerobic exercise, such as walking, cycling, and swimming, can increase the ketone levels in your blood. In fact, if you’re diabetic with high blood sugar and high ketone levels, you may be told not to exercise to keep your ketone levels from skyrocketing. ^{[2] [6]}

On the other hand, anaerobic exercise – which includes high-intensity activities like sprinting, skipping rope, or heavy weightlifting – can decrease the ketones in your blood. That’s because ketone bodies are oxidized as fuel during anaerobic exercise. ^[6]

For most people, this information is moot, as the right balance of a low-carb, high-fat diet, proper exercise, and good vitamin and nutrient intake will ensure you meet your ketosis and weight loss goals. But if you’re monitoring your ketone levels closely, knowing which types of exercise cause them to fluctuate can be a useful piece of information.  

How to Check Your Ketone Levels

And speaking of: now that you know where your ketone levels should be, you may be wondering how to check them. Fortunately, you have several options.

The most accurate method is a blood ketone meter. These work similarly to a glucose meter – just prick your finger, squeeze a drop of blood onto a test strip, and let the machine work its magic to measure the ketones in your blood. ^[2]

Urine tests are slightly less accurate, but they involve significantly less blood. All you need is a test strip and a full bladder. These tests indicate your ketone levels by changing color: the darker the strip, the more ketones are present. ^[2]

Breathalyzers are the most expensive method of tracking ketone levels. These devices measure the acetone concentration of your breath. As a ketone byproduct, acetones can approximate your ketone levels without requiring blood or urine. ^[7]

But no matter which method you prefer, each one can help you track your progress as you continue on your ketogenic journey.

Sources

1. https://www.webmd.com/diabetes/type-1-diabetes-guide/what-is-ketosis#1
2. https://www.webmd.com/diabetes/ketones-and-their-tests
3. https://medlineplus.gov/lab-tests/ketones-in-blood/
4. https://cdnstatic8.com/revolucaoketo.com/wp-content/uploads/2019/07/105685548-Art-and-Science-of-Low-Carbohydrate-Living-Phinney-Stephen-Volek-Jeff.pdf
5. https://www.cdc.gov/diabetes/basics/diabetic-ketoacidosis.html
6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5407977/
7. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4737348/

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