Fasting, autophagy, and fat supplementation

(G. Andrew Duthie) #1

Hoping someone with a better understanding of the underlying science can help here.

When I fast, I typically do it for two reasons:

  1. To break through a stall, or reverse weight gain.
  2. To take advantage of the benefits of autophagy (see here for more info from Dr. Fung’s site)

Dr. Fung, who is of course a major advocate of fasting “allows” the use of supplemental fat and/or HWC as a means of increasing the ability to fast. At the same time, if @richard’s post here is accurate, in my case extended fasting may require the use of additional fat to make the fast possible, as I no longer have sufficient body fat to supply my daily energy requirements.

My question is this: will the addition of fat intake prevent the process of autophagy from taking place? Given that, per Dr. Fung, the driver of autophagy is glucagon, which is the mirror of insulin (i.e. one rises, the other falls), intuition says “no” but I’d love to hear from anyone who is aware of any research into this specific area.

Does cream in my coffee confound a fast?
How can I tell ? Fasting
(G. Andrew Duthie) #2

Paging @erdoke. :slight_smile:

(Ross Daniel) #3

My understanding is that as long as you aren’t supplement protein, you’re good to go. Must be pure fat. MCT oil, ghee, etc. But I’m no expert :smile:

(Richard Morris) #4

Anything that raises insulin will shut it off, as will the amino acid leucine.

Does cream in my coffee confound a fast?
(G. Andrew Duthie) #5

OK. Next question, then, is whether it’s an On/Off switch, or more like a spigot, where some insulin will reduce the amount of autophagy, but not stop it completely.

I continue to wish for a simple at-home test for insulin levels, which would greatly simplify the ability to track how insulin rises/falls with various food intake.

(Richard Morris) #6

There are very few binary switches in the human body.

I suspect it’s a continuum of increasing inhibition. but I don’t have any evidence to prove it.


I’m really fascinated by the whole concept and science of autophagy. I did a 33 day fast in November/December. I only had water, coffee and tea. I did have broth about once per week and multivitamin twice per week. I noticed weightloss stalls and weight gains when I had the broth, multivitamin or seldom time when I added cream in my coffee. I was pretty surprised when I saw that taking a multivitamin would create a stall or gain. My guess is that it was just water retention, because the next day or two I’d get a greater than normal weight loss plunge. I learned that in fasting, it is worth changing only one variable at a time and have patience to see what effect it makes.

(G. Andrew Duthie) #8

Any possibility that the multi had some starch in it? Shouldn’t be enough to cause issues, given tablet size, but maybe the effect could be exaggerated while fasting?


@devhammer, what brilliant insight! That’s a fantastic question. You may be right…i will check. By the way, it was a regular Centrum multivitamin.

thank you for that brilliant insight!!

(G. Andrew Duthie) #10

You’re welcome, but too kind by far. :slight_smile:

(Gabor Erdosi) #11

I believe if you spread out smalll amounts of pure fat during the day the insulin response to those should stay well below the autophagy radar. Make sure to avoid all carbs and protein though, so even HWC should be banned.

(L. Amber O'Hearn) #12

That is interesting, given that fasting (and keto dieting, which also itself induces autophagy) increases blood levels of BCAAs including leucine. My understanding is that it is part of the protein sparing mechanism.

(joievawter) #13

I don’t have actual scientific research other than my own N=1, but when I do an extended fast of anything over 24 hours my bf % goes down a few 10ths of a percentage and I am very hydrated and I consume some butter or hwc or coconut oil (limited to a tsp), whatever I am feeling. Only when I am cold though so, maybe once during 36 hours.


Having a heck of a time trying to get the non active filler ingredients in centrum vitamin. Website doesn’t provide info. According to Livestrong website, it contains glucose as part of filler. I will have to test another multivitamin in another fast to see if I get same or different effect.


The tricky part here is that autophagy actually releases leucine as cells are catabolized. Some cancers, melanoma for example, will live on just this intracellular leucine.

The mechanism by which leucine works it’s the MToR pathway, which makes leucine anabolic (in the presence of other proteins) in doses of around 2-3g. So somewhere between 0 and 2g would be a threshold of some kind. I have yet to find a specific measurement for this.

Linky link:


(G. Andrew Duthie) #16

I would be very surprised if this didn’t vary significantly from individual to individual.

(Christina) #17

I’m doing a 20:4 today. My longest by far and I’m hoping to build up to an extended fast.

I’ve read about using pure fat in the fast to combat any feelings of hunger or cold. So today I’ve had 2 small coffees with about 15ml of cream in each. Is this not OK? Am I sabotaging the gains from fasting?

(G. Andrew Duthie) #18

From what @richard has said in a couple of threads, HWC may be problematic if your goal (or a goal) for fasting is triggering autophagy. HWC has some carbs (0.4g per Tbsp, IIRC), and a small amount of protein. Better, if you want to supplement with fat, to stick with grass-fed butter, coconut or MCT oil.

That being said, I do use a little HWC in my coffee during fasting, but I am very careful to measure it and limit to 1 Tbsp, whereas when I’m not fasting, I am a little more liberal in the use of HWC.


For me, HWC sabotages my fasting efforts. My guess is that there is a slight insulinogenic effect. I drink my coffees and teas without anything added.

But, that’s the case for me. I think it is worth testing the variables to see what effect it has on you.

(Sascha Heid) #20

What do you think about this:

"Well here’s the thing, dietary fat blunts growth hormone secretion. This is because fat raises somatostatin, which is a growth hormone inhibiting hormone. So by consuming plenty of fat during your fasts, you’re actually negating one of the primary benefits of intermittent fasting, the massive increase in growth hormone secretion.

So with a fat only meal, you will indeed have low levels of insulin (fat doesn’t spike insulin – protein and carbs do), but this doesn’t mean you’ll be able to burn body fat. To maximize fat burning you need to have low insulin levels and elevated growth hormone."