How Long Does it Take to Get into Ketosis?
Short Answer: 2-7 days
In order for your body to get to the point where it is breaking down stored fat into ketones for fuel, it must first use up all stored sugar. The body stores excess sugar in the muscles in the form of glycogen. It is stored there to give the muscles access to a quick source of energy should the need arrive. You must first deplete the glycogen so the body is forced to use fat for fuel instead.
There is about 2-3 days worth of sugar stored in your muscles so if you keep your carb intake at around 20g a day, you should deplete those stores within 3 full days. You can speed up the process by either fasting or exercising. The fasting will keep the body from creating new sugar from food intake and the exercise will cause the body to burn off the sugar faster.
If you are using a ketone tester, you should start seeing a ketone reading by the third day and start seeing them increase over the course of the next 2 weeks to a month. As your body begins to use ketones more efficiently, you should see ketone levels drop to right about .5 mM can go as high as 5 mM.
Any questions? Leave them in the comments below and I’ll answer them. Thanks!
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I understand this is what happens if you are new to low carb dieting, but what if you gave used low carb diet on and off for over 40 years? I have abused my metabolism yo yo dieting since Dr. Atkins, low carb, High protein, high fat lower protein now, how does this affect getting into and sustaining ketosis?
Great question. The good news is that the body has a remarkable ability to repair itself when you give it half a chance. The key here is to start LCHF and sustain it for a long period of time. It might take a little longer for you to see results but the biochemistry is solid. Once your body no longer has access to glucose, it will have to break down fat to live.