Need Explanation Please "WHY FASTING IS EASIER FOR SOME PEOPLE"


(Sjur Gjøstein Karevoll) #7

The 31.5 calories/pound body fat per day comes from the Minnesota starvation experiment, and I’m not entirely sure if it applies to fasting. During the experiment the participants were fed approximately half their calorie requirements from food consisting mostly of starchy vegetables (potatoes, rutabaga etc.) and not much protein. This doesn’t necessarily reflect true fasting physiology or even a low-carb fed physiology. No other experiments have reproduced the number under different conditions so how it changes with diet and body composition is unknown. There is anecdotal evidence from people fasting or losing weight in other ways suggesting the rate of fat loss can be higher, perhaps much higher, than the Minnesota starvation experiment suggests.


(Liam) #8

Hmm well I just throws a monkey wrench in this whole operation haha, is there any quantification of fat loss in those anecdotal reports that you’ve seen?


#9

Just want to add that although many folks find that calculator helpful, I also have my doubts for the same reason that @Berengal mentioned (that experiment is so different from fasting, and those poor fellows’ diets were so different from keto!). Based on the calculator I should have been a rag on the floor during my last 5-day water fast and instead I was feeling amazing and rocking my Bikram classes.
There are many factors, I’m sure, and as you keep playing with fasting you’ll start to get to know your own body and your own tendencies. It certainly makes sense that leaner folks can’t fast for as long but I’m not sure there’s a clear formula for exactly how much energy we can get from our own fat stores.


(Liam) #10

Yes thanks I agree, my main interest in fasting is for the health benefits and to lose his little muscle as possible, I am not trying to lose weight at all, to me feeling painfully hungry indicates having a little fat, which I’ve started doing only when I feel hungry rather than following the amount specified in the calculator. Is there any info from 2ketodudes or otherwise that talks about avoiding muscle loss? Are amino acids helpful or?


#11

I’m not an expert on fasting and I don’t really know how to answer your question fully, but it seems like for now you could keep your fasts on the shorter side (24-36 hours), tracking your own experience, and in the meantime do a lot of research.

I’ve heard - in interviews with Valter Longo, Jason Fung, and Dom D’Agostino - that even in lean folks the muscle loss is negligible in short-term (2-5 day) fasts, and whatever you might lose is quickly built up again. Also keep in mind as you do your research that a lot of the panic about muscle loss during fasting seems to be based on a certain amount of protein breakdown that was assumed to be lean muscle but is more likely the natural result of autophagy (cleaning up and recycling of older cells in the body, many of which are made of protein - ligaments, tendons, etc).

Taking in amino acids during the fast will inhibit autophagy, so I wouldn’t do that, but I guess it depends on your reasons for fasting (exactly which health benefits you’re looking for).


(Richard Morris) #12

I agree, it’s from Ancel Keyes’ MDS, and the guy has form for hiding data. But in this case he had no idea what
Seymore Alpert would eventually be looking for in Keyes’ data some 60 years later so I wouldn’t discount it on that basis.

It is true that this was not a fasting study. This was a starvation study to feed men a diet that would cause them to lose 1.1kg per week. Subjects experienced dramatic energy shortfalls (Subjects average body temperatures dropped to 95.8F = 35.4C) and experienced sever mental distress that it would probably be unethical to repeat the experiment today. One guy apparently chopped several fingers off with a Hatchet to try to get out of the study.

Alpert wasn’t a physiologist, he was drafted into the Army while in 2nd year med school, and after the war he switched to do a PhD in experimental physics. What he did here was use math. He took a mechanistic formula for weight loss from first principles, plugged in as many known values as he could (including many that were just not known in Keyes’ day), applied the observed values from the starvation experiment to generate a formula that he could integrate and project it to come up with a value for the maximal rate of fat drawdown based on people losing 1.1 kg/week.

I would love to see someone measure the rate of drawdown by people fasting, and eating hypo-caloric amounts of many different macronutrient ratios, and with people with dramatically different body compositions.

It’s kind of like measuring the height of a mountain by going and climbing it carrying a barometer.

What Dr Alpert did was the equivalent of using a protractor and a sight line from sea level to give us a decent approximation.

Papers that cite his paper are serious ones from serious researchers so until someone redoes the experiment and finds a different value I think it’s probably going to be the closest we’re going to get.

BTW there was a lot of interest recently in incredible rates of energy release from fat in fat adapted athletes in Jeff Volek’s FASTER study, numbers that have rewritten the record books on how fast humans can burn fat. That is a different question to answer than how fast humans can release fat to be burned. The FASTER subjects all had a big fatty meal the previous night and drank a fatty milkshake before getting onto the treadmill … so they supplemented what they were able to draw from body fat with lipid pools already in cells, and lipoprotein lipid carriers in circulation (Cylomicrons, LDL, and Albumin)

I have not seen anyone improve on Dr Alperts calculation. But would be very happy to find one.


Fasting for slim folks
(Liam) #13

Thank you so much I love all those people you mentioned and I’m an avid listener to podcasts that feature them. I suppose I look at fasting as one of the most powerful preventative medicine things I can do for myself being almost 50 years old and at the same time being at that age it’s vital to maintain if not build as much muscle as possible. Your answer here relaxes me quite a bit about all this and I think you’re right, thanks.


(Karen Parrott) #14

I haven’t read the other responses but fasting works great for me because I have genes that code for addiction (food) , T2D and ghrelin (extra hunger hormone). Fasting/LCHF/Keto puts my body into a good hormone signaling and I get somewhat normal full/hungry signals 85% of the time.

All highly theoretical, but worth mentioning. I don’t chase ketones, but by chasing different fasting protocols, I chase normal hungry/full signals, normal glucose levels, a lean body, better sleep in menopause and normal body weight after 40 years of obesity. 5.5 years weight maintenance. Almost diagnosed type 2.

Paleo/LCHF/Keto/Fasting = easier than high hs-CRP/almost type 2 diabetes/normal hungry/full = lid on binge eating 85% of the time.

Onward. Hope this post makes sense. I can get “high” from ketones as well as I can get “high” from a Skinny Cow Ice-cream studded with M&M’s and counting points. One gives me better results. LOL. EZ.


(Richard Morris) #15

Yep Amino Acids (or carbohydrates) will raise insulin which will stop glucagon mediated autophagy.

Fat is potentially sparing of lean tissue loss. Let me lay out the theory.

So the Alpert study calculated the maximum rate we can get energy from body fat. So let’s say you have 10lbs of body fat, that is roughly 35,000 kCalories of energy (1lb of body fat being worth roughly 3,500 kCalories). Alpert shows us that from the same 10lbs we can only draw down 315kCalories every day. So it’s like an ATM daily transaction limit. You might have $35,000 in your bank account, but through the ATM you can only withdraw $315 every day.

So if you think about someone with 30lbs of body fat and someone with 60lbs of body fat, both going on a fast. When the first person fasts they have a daily budget of 945 kCalories from body fat - the second person has a daily budget of 1890 kCalories from body fat.

Most people need around 1500 kCal/day, let’s stipulate that both of these people use that much energy. The person with 60lbs of body fat is good to go, they have an extra 390 to play with.

But how about the first person with only 30lbs of body fat? They have already tapped their maximum fat reserves. They need to make up the the shortfall of 555 kCalories. The only source available to a fasting person is to use amino acids, by breaking down protein structures in their own bodies. That is a draw down of around 140g of lean mass every day.

That’s why I usually suggest that people who are lean shouldn’t fast, or if they do they should supplement with dietary fat to prevent loss of lean tissue.


(Adam Kirby) #16

Is fat-assisted fasting worth it for a lean person, for the autophagy?


(Richard Morris) #17

Fat shouldn’t raise insulin, which won’t inhibit glucagon mediated autophagy. So yes I would say that is appropriate.


(Mary) #18

Hello all!

This is my first post. I’m so thrilled to find this forum! Even in these supposedly enlightened times, fasting seems to be something that one shouldn’t shout from the rooftops. So I’m shouting here… Glad to find some like-minded individuals.

This is the first time I’ve heard of “the maximum rate we can get energy from body fat”. Fascinating! Let’s see if I’ve got this right - my goal is approx 135. At 20% BF (27 lbs) my lean body mass should be about 108 lbs. I was 218 this morning which means I’m carrying 90 lbs of fat (yikes) which should yield all the energy I need for the day. Would I be correct in assuming that as I lose BF (40 lbs or so), I’ll need to supplement with fat to make up the energy shortfall?

I’m on day 6 of an extended fast which will end when I feel the need. Must make up that electrolyte recipe…


(Mary) #19

Oops - terrible math. I’m carry 110# of fat.


(Liam) #20

day 6 huh? congrats! I’m on day 4 and have felt SO WEAK, like can hardly walk very far etc… am doing the fat as per the calculator, not sure how much it’s helping on the energy front, certainly hope it’s helping on the “not losing muscle” front tho! Hearing so many people here talking about how amazing they feel on their fasts, definitely not the case for me ugh


(Liam) #21

By the way what is that electrolyte recipe you’re talking about?


(Jim Russell) #22

https://www.ketogenicforums.com/t/ketoaide-homemade-ketoade/5198

I haven’t been able to find the bottled magnesium drinks, so I bought some magnesium citrate powder and put about 1/2 tsp. I also cut the lite salt down a little and add sea salt. I use the water flavoring drops like Mio for flavoring. It works great.


(Liam) #23

thanks man!


(Tim W) #24

Are you in the US? I can find the liquid mag citrate at nearly every grocery store and pharmacy in the laxative areas.


(Jim Russell) #25

Ah, I was looking in the vitamin area. I will have to check the laxative area. But I’m happy with the way I have been doing it.


(Liam) #26

Hey Jimbo, curious if you’ve heard any talk about coffee while fasting? Like does it interfere with any of the benefits of fasting? How much is too much? It’s basically what’s been keeping me going and I feel a little guilty with how much I’ve been drinking while I’m supposed to be cleansing LOL