Dry Fasting. Is there any science to this?


Fung mentions it regularly … in a DON’T DO THIS kind of way. :slight_smile:

(DougH) #216

Thanks @OldDoug :rofl: My high school chemistry teacher would be kicking me in the rear, I forgot to consider the mass of the oxygen being introduced through respiration.:zipper_mouth_face:

(Doug) #217

Doug - this stuff is very interesting. Birds that migrate long distances and some desert-dwelling creatures have some awesome adaptations to make and conserve water. We humans, not so much.

(Jane) #218

I haven’t seen anyone that has dry fasted report they lost as much fat in one day as 3 days of water fasting. So there’s that.

And IF the body makes its own water from fat there is a limit to how much it can burn for that so the metabolism would just start dropping to compensate for the lack of energy available, right?

(Doug) #219

Jane, am currently talking with people on Youtube who swear they lose more while dry fasting versus water fasting. Nobody has specifically said “three times as much,” but they insist it’s definitely “more.”

The “dry fasting is 3x faster than water fasting” thing is very pervasive, though, as a claim. Among the reasonable-sounding people who swear they lose fat more quickly on a dry fast, there’s a morass of some outright falsehoods propagated by dry-fasting advocates, a lot of wishful thinking, and the fact that the length of the fasts are so short as to render weight measurements useless as a fat-loss gauging tool. Any truth in there, if it exists, is swamped by the other factors.

Totally agree - I see no way of getting around what is apparently quite a hard limit on fat burning, a la “A limit on the energy transfer rate from the human fat store in hypophagia.”

As far as making water from fat - that could have a meaningful effect on our hydration while dry fasting - it does not happen (from everything I’ve read). We start off by consuming 3 water molecules in the breaking down of every triglyceride molecule, so we’re at a net negative thus far. Eventually, some water is indeed created, as the byproduct of cellular respiration/metabolism, but the vast majority of that goes to the lungs and is exhaled, along with carbon dioxide.

A white fat cell has a very thin layer of cell membrane around the outside that contains the cytoplasm, nucleus, mitochondria, etc. - the normal cell parts. Then there is a relatively huge droplet of fat in the middle. Very little water, overall, and the cell cannot afford to lose it from the cytoplasm. It’s a common thing to hear the like of “There is water in fat and our body rushes to get it while dry fasting.” Here too, as far as I can tell, that’s just wrong.

(Diane) #220

Hmmm… the other side of this discussion has gotten very quiet.


(Jane) #221

Thanks @OldDoug for taking the time to research this. I came to the party late but you are catching me up fast! (pun intended)

I don’t have any desire to try it myself. Fasting w/o my BPC is hard enough sometimes. I just feel for me it would put undue stress on my body.

But an interesting topic.

(Running from stupidity) #222

I do, even though he’s a chiro AND he’s flogging stuff. One of the very few keto podcasts I can still be bothered listening to.

But that’s not the same as totally believing everything he says and writes :slight_smile:


(Doug) #223

Heck, I wish there was something to it…

(Running from stupidity) #224


(Diane) #225

Not me. I don’t like dry fasting and I feel just fine being convinced that I have no good reason to ever do it again.


(Running from stupidity) #226

You’d still have the option to do it or not, it wouldn’t be mandatory :slight_smile:

(Mel Simpson) #227

I dry fasted for 36 hours a couple of weeks ago and it was surprisingly easy. I did not feel thirsty or have a dry mouth at all. That said I am not a great water drinker
. I dont think you dry fast or water fast for weight loss.it is said to be more for cellular regeneration and a 24 hr dry fast is said to be equivalent to 3 days of water fasting. The biggest weight loss I have had was doing a fat fast

(Running from stupidity) #228

Yeah, but the question is “Is there any science to it.”

(It's all about the bacon, baby) #229

Simple! Get 200-300 people, put half of them on a water fast, half on a dry fast. Measure the results. Publish!

(PSackmann) #230

I’m not a science person, but have any of the studies or articles mentioned ammonia levels in the blood due to a dry fast? I’m asking because of what I experienced with my mother. when she developed biliary tube cancer, she also developed a UTI, became dehydrated, and her mental functioning and cognition were negatively impacted. I learned that dehydration is the biggest issue facing assisted living centers (ever wonder why they all have infused water in every public area?). Anyway, this whole discussion on dry fasting made me wonder how many people, without knowing they had some type of potential impairment, would attempt a dry fast and end up negatively impacted.
It took my mother a month in an in-patient center to be considered stable enough for a memory unit, and another month of careful diet and hydration to get into “general population” (her words).
Just another cautionary thought before attempting

(Mel Simpson) #231

And the answer is yes there is one study that was fairly robust and showed that there was value to dry fasting

(Mel Simpson) #232

Can cell regeneration be measured? Or what are we measuring?

(DougH) #233

No there aren’t any easy bio-markers for autophagy or apoptosis. I am sure there are in a medical study context, but it isn’t an off the shelf test. We just have to infer based on what we know is happening during a fast.

Can you share the study you mention above?

There isn’t money in fasting, there is nothing to sell! We should be happy if there are meaningful studies about fasting in any context, but I certainly won’t hold my breath for a proper study to come along that compares dry fasting to water fasting.

(Karim Wassef) #234

they’re working on it