Understanding the Ketosis Spectrum
For individuals following a ketogenic diet or a low-carb lifestyle, monitoring blood ketone levels is a common practice to confirm they have entered ketosis. Ketosis is not an on/off switch but rather a spectrum of metabolic states, with nutritional ketosis being the target for most people. While the transition can take a few days, a reading of 0.7 mmol/L confirms the body has shifted its primary energy source. This process begins after your body depletes its glycogen (stored carbohydrate) reserves. Once those stores are low, the liver begins to convert fatty acids from both dietary fat and stored body fat into ketone bodies.
What Different Blood Ketone Levels Mean
The ranges of ketone levels can be broken down to give you a more precise understanding of your body's metabolic state.
- Below 0.5 mmol/L: This is the normal, non-ketotic range. Your body is primarily using glucose for energy.
- 0.5–1.5 mmol/L: This is light nutritional ketosis. A 0.7 ketones reading falls squarely into this range. At this stage, your body has successfully made the metabolic shift, and your ketone production is above baseline.
- 1.5–3.0 mmol/L: This is the moderate to optimal range for nutritional ketosis, often sought for accelerated weight loss and maximum fat-burning effects.
- Above 3.0 mmol/L: While still within the safe range for nutritional ketosis, higher readings aren't necessarily better for weight loss and may simply indicate greater ketone production without additional benefits.
- Over 8.0–10.0 mmol/L: This is an extremely high and dangerous level, which is most often associated with diabetic ketoacidosis (DKA), a life-threatening condition that requires immediate medical attention.
Blood, Breath, or Urine: Which Ketone Test is Best?
When starting a ketogenic lifestyle, many people wonder which method is most reliable for monitoring their ketone levels. The three main methods are blood, breath, and urine testing. Each has its own pros, cons, and accuracy levels.
| Feature | Blood Test | Urine Test | Breath Test |
|---|---|---|---|
| Accuracy | Most accurate, provides a real-time snapshot of ketone levels. | Least accurate, shows past ketone excretion, not current levels. | More accurate than urine strips, but less precise than blood testing. |
| Measurement | Beta-hydroxybutyrate (BHB), the most abundant ketone in the blood. | Acetoacetate, a ketone that is excreted in urine. | Acetone, a ketone that is exhaled. |
| Cost | Highest initial cost for meter, plus recurring cost for strips. | Lowest cost, but strips are disposable and accuracy is inconsistent. | Moderate initial cost for the device; no recurring cost for strips. |
| Convenience | Requires a finger prick and a blood sample, similar to a glucose test. | Non-invasive and easy, but results can be skewed by hydration levels. | Non-invasive and simple, provides a reading quickly. |
For a precise and reliable measure to confirm if 0.7 ketones ketosis is present, blood testing is the gold standard. Urine strips, while inexpensive, can become inaccurate as your body becomes more keto-adapted and uses ketones more efficiently, meaning fewer are excreted in urine.
What to Do with Your 0.7 Ketones Reading
If you have a blood ketone reading of 0.7 mmol/L, congratulations—you are in ketosis. This is a sign that your dietary changes are working. This reading is an excellent starting point and a clear indicator of metabolic change. To potentially reach the optimal range of 1.5–3.0 mmol/L, you can fine-tune your approach.
- Reduce Carbohydrates Further: The most direct path to increasing ketone production is to decrease your daily carb intake. Most people aim for 20–50 grams of net carbs per day.
- Increase Healthy Fats: Ensure your diet is rich in healthy fats, which provide the fuel your body needs to produce more ketones. This includes avocados, olive oil, nuts, and fatty fish.
- Incorporate Intermittent Fasting: Fasting, even for short periods like 16 hours, can accelerate the depletion of glycogen stores and speed up the process of ketosis.
- Incorporate Exercise: Physical activity, especially fasted workouts, helps deplete glycogen and encourages your body to burn fat for energy.
Potential Benefits and Side Effects to Be Aware Of
As your body adapts to using ketones, you may experience several benefits, including improved mental clarity, reduced appetite, and increased energy levels. However, the transition can also cause temporary side effects often called the 'keto flu,' with symptoms like fatigue, headache, and irritability. Staying hydrated and ensuring adequate electrolyte intake (sodium, potassium, and magnesium) can help minimize these effects.
Conclusion
A blood ketone reading of 0.7 mmol/L confirms you have entered the state of nutritional ketosis. While at the lower end of the spectrum, it's a positive sign that your low-carbohydrate approach is working. Tracking your levels with a blood ketone meter is the most accurate way to monitor your progress and make adjustments as needed. For those aiming for higher levels, slight modifications to your diet and lifestyle can help deepen your state of ketosis. Always consult with a healthcare provider before making significant dietary changes, especially if you have pre-existing health conditions like diabetes, to ensure ketosis is a safe and appropriate goal for you.
Source: UChicago Medicine, "Is the Keto Diet Safe? What are the Risks?" (2023)
