Are you changing your long term fasting length after listening to the Phinney interview?


(PJ) #21

Adipose cells vary a little depending on type, but last I read, their official life span is eight years. However, the life span of the content within them has a half-life of two years. So there is more to the question than merely the overall cell.

I consider fasting studies the only comparison for actual fasting. One thing that the research does seem like it makes clear is that there is a difference between under-eating (resulting in making one a ‘competitive eater’ and ‘competitive survivor on minimal calories by reducing metabolism’) and not-eating (resulting in making one a ‘competitive hunter’ and ‘competitive survivor on no calories by increasing metabolism so you can hunt for more, or you’re screwed’).

So for example, while the results of Keyes’ studies on this are fascinating, I consider it an excellent example of what happens when people are anorexic or diet (in today’s world) – not a good comparison for people who do short term fasting.

PJ


(PJ) #22

Here are a couple of PDFs (just for locals) some may find interesting on the topic.

A summary ~15 years ago from Cahill

Physiological adaptation to prolonged starvation - refs Cahill, has neat visuals :slight_smile:

297122878-Fuel-Metabolism-in-Starvation.pdf (536.6 KB)
derangedphysiology.com-Physiological adaptation to prolonged starvation.pdf (873.3 KB)


(It's all about the bacon, baby!) #23

True, and even Phinney doesn’t really disapprove of a fast that lasts only two or three days. And remember, past 2-3 days, even Fung wants you to have medical supervision.


(Haleigh S) #24

Autophagy is a hugely beneficial process, overall, although there is at least one study I’m aware of that shows the opposite That may be the one that Dr. Phinney referred to.

It is the process by which the body gathers up old cells/sick or dying cells/misfolded proteins, and recycles them through a process of “self-eating” (the literal root translation for autophagy).

Autophagy begins at approximately 20 hours fasting and the benefits last until ~120 hours, at which point the chart shows a steep decline in benefit. The body uses the fuel gathered from this process to begin regenerating stem cells throughout the body as soon as the fast is broken.

Intestinal stem cells are targeted around 24 hours, and the immune system stem cells around 72 hours, from what I’ve researched. Check out Valter Longo’s studies, as well as the studies that were done as a result of his work.

There is a cumulative effect from these extended water fasts, and while they shouldn’t be overdone, properly spaced water fasts over a period of time, with appropriate nutrition in between, have been proven to have some incredible health effects in addition to weight loss, including repair of muscle and bone, tumor reduction or death and the cure of long term chronic illnesses.


(Karl) #25

A quote from Dr Jason Fung:

During fasting, there is a period of time where protein is being catabolized (broken down) to burn for energy. This is not a bad thing. In this case, it is very good. Obese individuals have an estimated 20-50% more protein than lean people. This is all extra tissue that needs to be removed. In the IDM program, we’ve had people lose hundreds of pounds, just like Robert, and we’ve never referred anybody for skin removal surgery.

Maybe the loss of non-fat tissue is another benefit of fasting?


(Windmill Tilter) #26

Frequent extended fasting is so poorly understood that nobody can do anything other than speculate as to what happens to the human body as a result (apart from fat loss). Both the cheerleaders and the alarmists don’t have much to work with other than studies of individuals fasting for the first time, which aren’t really applicable.

We barely understand autophagy. On top of that, a*All extended fasting research to date has been conducted on subjects fasting for the first time.** No research has ever been conducted on a subjects performing extended fasting for the second time, much less the twentieth time. No one knows what metabolic adaptations occur. No one know how autophagy changes in response to repeated extended fasting.

You may surmise from the facts above the repeated extended fasting is safe and uniformly positive. Bless your heart.

The one person with the most data on how repeated extended fasting affects metabolism is Dr. Fung. He used the term Resting Metabolic Rate (RMR) 100+ times in the obesity code. Have you ever seen Fung’s data on how repeated extended fasting affects the RMR’s of his clinic clients? Neither have I. He does tell us perform 72hr fasts no more than 4 times per month; probably smart to listen to that one.

That said, I did a few dozen 84hr fasts last year. This year I’ll be doing a similar number of 60 hour fasts. I have a measurable metabolic adaptation from this. My RMR drops precipitously (250kcal/day) as exogenous calories are exhausted and my body switches over to lipolysis. It’s unlike anything ever recorded in the literature on subjects fasting for the first time. I know this because I own an indirect calorimeter that allows me to test my RMR daily. I’m not the only one; there is another forum member who does frequent extended fasts, who measures RMR daily, and whose RMR drops 500kcal/day on the first day of each extended fast he performs (that’s a staggering drop). I have no idea if this adaptation is benign. I have no idea what other adaptations are occurring. No one does. I’m ok with the risks.

Phinney isn’t necessarily wrong, nor is Dr. Fung. The former has no evidence to work with, the latter has never published evidence that it’s safe.