Nutritional ketosis happens when dietary carbohydrates are significantly reduced (<50 grams per day) and the body’s production of ketones increases to maintain a blood level at or above 0.5 mM.1 When you restrict carbs below 50 grams and consume a moderate amount of protein it is normal to have ketone levels of 0.5-3.0 mM. It should be noted that every person’s ability to get into nutritional ketosis is different. Some people will see increased ketone levels after just a few days of restricting carbs while others will take 1-2 weeks before their ketones start to increase, particularly if they are taking medication for diabetes. Thus, it is helpful to work with an expert on the ketogenic diet to help guide you through the process.
Once your body achieves blood levels in the nutritional ketosis range, it then begins a process called ‘keto-adaptation’. In the first few weeks of this process, you may find that your exercise endurance is limited, but this typically resolves after 3-6 weeks. Other processes in your body are then fine-tuned over 2-3 months to achieve all of the benefits of ketones as a clean-burning and efficient fuel. This complex process is addressed in our blog post on Keto-Adaptation.
Volek JS, Phinney SD. The Art and Science of Low Carbohydrate Performance. 2012. PP 4-5. Beyond Obesity Publishing, Miami FL.