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

(Liam) #1

is this calculator in the link below telling me how much fat I should eat while fasting? I thought eating fat while fasting takes away some of the benefits of fasting. This says I need to eat 166g of fat per day while fasting, what would be the best sources of this fat? MCT oil? thanks

(Jim Russell) #2

That seems like a lot. If you don’t mind me asking, how much do you weigh and what is your body fat percentage? It seems like you have to be both pretty large and lean to need to add over 1500 calories to your fast.

(Liam) #3

I thought so too, I’m 6’1" 175 lb, not sure what my body fat percentage is … Just estimated my lean body massage using online calculators at 141lb

(Jim Russell) #4

Hmm… I think you may have gotten something wrong with the calculator. I just put those numbers in and it says 103 grams. Which is still a lot. :slight_smile:

Ok. Here’s my understanding of how it works. Your fat cells can only release fat at a certain maximum rate, 31.5 calories/pound according to @richard’s research. So if you have about 34 pounds of fat, your fat cells are only going to be able to release about 1000 calories per day. Fasting is not about starvation, it’s about not eating. So if your metabolic rate is around 2000 calories, then if you don’t eat anything and your body is only able to burn 1000 calories of stored fat, you are going to be hungry. That hunger signal is your body telling you that it’s input and output are pretty poorly matched up and if you don’t feed it then it will start to slow your metabolism (output) to match your input.

So, the thing to do is to eat something so that your input and output are more closely matched. Since you’re fasting, you don’t want to eat protein or carbs as they will cause an insulin spike. So you need to eat fat.

As for what kind, coconut oil, butter, olive oil… Whatever works for you.

But… If it were me, I would start the fast and only add the fat if I felt like I needed it.

It also depends on how long you are planning on fasting. You would probably be fine for intermittent fasts, but extended fasts are where the issue would show up.

Best of luck to you and let us know how it goes.

(Liam) #5

Thanks so much! Makes perfect sense the way you explain it. I used a metabolic rate of approx 2500 based on some online calculators that factor in activity level, age, height, weight etc… should I not have done it that way?

(Jim Russell) #6

No, that’s an important number. The “output” in my explanation. That is the number you need to match, or at least come close to matching with the fat from your body + the added fat. As I said, if it were me, I wouldn’t necessarily shoot to hit that number, 166 grams of fat. I would start my fast, maybe with some fat. I forgot to mention heavy whipping cream. It’s awesome with coffee. So I would probably add some heavy whipping cream to my first cup of coffee, then I would just play it by ear as far as added fat goes. If you feel weak or tired, add some fat. And make sure that you keep up with your electrolytes.

(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