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So I searched around for a while but couldn't find a definitive answer (maybe there isn't one), does intermittent fasting induce ketosis? I usually IF overnight until lunch-time. I've read that sleep often induces ketosis. Am I in ketosis at the end of that fast?

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The Health Correlator blog has a good table for this:

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As you can see, people fasted for up to 24 hours have very slight ketone production, whereas those fasted for 2-3 days have relatively high ketone levels, but the upper end only the same as the upper end of those fed a high fat diet unfasted. I suspect that a big factor would be how much carbohydrate you're storing before fasting, which would determine whether or not you actually need to enter ketosis while asleep. From the look of the table (I can't see any more details since it's from an encyclopedia, not a journal paper) it would seem that exercising (perhaps after the end of your fast), could induce more ketosis than a short (12-24 hour) fast.

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Cool table, thanks for this! – ChadHydro Jan 24 2011 at 19:00
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 I think eating certain highly ketogenic fats like coconut oil will lead to a high concentration of ketones without necessarily even cutting back too far on carbs. – Travis Culp♦ Jan 24 2011 at 19:10
@Travis It does in the short-medium term, but I remember reading somewhere that over time the body adapts to metabolise MCT in much the same way that it metabolises LCT, but I'll need to look it up. – David Moss Jan 24 2011 at 19:20
"Fed normal diet" doesn't really say anything does it :P? – Korion Jan 21 2012 at 19:24
I like the fact that they contrast the 'normal diet' with high fat at least, rather than insisting that the SAD is high fat. – David Moss Jan 22 2012 at 8:25
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In my personal observation, fasting for 15 hours everyday for three days along side a low carb diet high in good fat, and lots of black coffee sets me into Ketosis. I also workout while still fasted.

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How do you measure that you're in ketosis and the depth? – Alan Jan 29 2011 at 13:45
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 I'm not sure about the depth, but I judge by the sudden energy level increase, mental clarity, and clear and copious urine. It's not as accurate as a ketone stick, but in the same ball park. – MF Jan 30 2011 at 3:27
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After exercising at the very end of a 20-hour fast, I showed a small amount of ketones, even though I am not on any sort low carb diet (low calorie, but not that low) and probably consume 90% of my calories in carbs.

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you should try bulletproof IF

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