Extended Benefits of Extended Fasts

As I noted in an update the day after my Stepping Off the Wagon post, I was shocked that after eating a whole pizza and more than one gluten-free beer, I was still able to stay in therapeutic ketosis.

Since Lisa and I concluded our #3DayCancerPreventionFast on January 27, in addition to January 31 we have stepped off the wagon two more times: February 11 and last night.

While Lisa has stopped the daily glucose and ketone measurements between our monthly extended fasts, I have kept them up since then. My readings for the 24 hours after the first excursion are above, and below are those for the period after the February 11:

I technically was out of GKI ketosis on the morning of the 12th, but by fasting as I stepped back on the wagon I was back to moderate ketosis by dinner time.

So because we’ve handled our off-wagon ventures with few negative effects, and because Lisa was away most of the day yesterday, we decide to exchange Valentine’s Day presents a day late. Here was hers to me:

Some in the low-carb/ketogenic community believe it’s essential to always rigorously limit carbs to avoid undoing all of the good of ketosis, and that one step off the wagon will undo weeks of effort.

They say it puts you right back to square one.

I cautiously disagree, at least for myself and for Lisa.

One way it could derail us would be if it became a gateway to ravenous, uncontrolled carbohydrate indulgence.

I’m confident that won’t be the case for us today, because it hasn’t led to this in the past.

We will enjoy our black coffee this morning, and fast until dinner.

The other way it theoretically could cause a problem would be if it reversed the fat-adaptation we had achieved. I think the ketone readings above in my post-pizza periods – all of them 0.5 mmol/L or higher – show that the ketone production is continuing.

That’s a secondary benefit of extended fasting, on top of a generally low-carb eating pattern.

In addition to activating autophagy and apoptosis, an extended fast flips the fat-burning switch to high gear.

The fundamental idea behind ketogenic eating and fasting is to restore metabolic flexibility the ability to use both sugar and fat for fuel.

Unfortunately, the typical American diet has so much sugar and starch in their various forms that it destroys fat-burning capability.

As I finish this post before starting work, and having just taken my morning readings, I’ve seen my ketones dip to 0.4 mmol/L, the first time I’ve been below 0.5 in a month.

So it suggests I probably should wait until after the next #3DayCancerPreventionFast for another pizza night.

Update: I tracked my “day after” glucose and ketones three times today, and here were the readings:

With plenty of carbs in my system from a whole pizza and a couple of gluten-free beers, and with the normal morning rise in glucose levels, I wasn’t too surprised that ketones dipped a bit further even at noon. But with only black coffee in the morning and coffee with cream at noon, I’m now solidly back into GKI ketosis.

Time for some scrambled eggs for dinner!

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Author: Lee Aase

Husband of one, father of six, grandfather of 14. Chancellor Emeritus, SMUG. By day I'm the Director of the Mayo Clinic Social Media Network. Whatever I say here is my personal opinion, and doesn't reflect the positions of my employer.

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