Fasting, calorie restriction and BMR

intermittent
(Eric - The patient needs to be patient!) #1

Years ago I was trained as a scientist and engineer. I operate as a manager and a software developer now. Sometimes my brain just won’t let go of paradoxes and the like.

I’ve read Jason Fung’s guide to fasting, some of the Verta Health Blogs and listened to probably a 100+ hours of video by leading doctors and scientists in the LCHF arena.

Studies prove that calorie restriction diets don’t work. Typically weight loss is not permanent. See below the Biggest Loser study.

But fasting is a form of calorie restriction in the sense that in a given period you are consuming less (or no) calories. Jason Fung has data that says BMR does not go down when fasting and we know that BMR does go down when you eat smaller meals for extended periods of time.

I am wrestling with this paradox. I’m thinking the form of calorie restriction that does not work is smaller meals. Can we agree on that?

So if fasting works (IF, EF) to lose weight and not lower BMR then the real key is the lack of insulin during fasting that makes the difference. I’m guessing some of you will say well “duh” but I have to point out that fasting is fewer calories and calorie restriction is fewer calories.

What say you friends and LCHF associates?

Please note that I am doing IF 18/6 and will start EF after my next set of blood work. So I’m not challenging the wisdom of fasting. Only pointing out the unspoken obvious.

https://www.amazon.com/Complete-Guide-Fasting-Intermittent-Alternate-Day/dp/1628600012

https://blog.virtahealth.com/

(Chris) #2

Fung doesn’t say that. He specifically says that when you break your fast, you have to FEAST in order to keep metabolism high. Otherwise, yes, you would be just calorie restricting and lowering your BMR.

I definitely fasted too much too often and paid for it, and now I only do it once in a blue moon. But the major takeaway is you must almost overeat when finished with your fast in order to prevent big problems related to metabolism.

#3

Fasting isn’t calorie restriction; it’s just a time when we have full access to endogenous calories.

#4

This is not to say that fasting can’t lower BMR, because I’m sure under some circumstances (not fat-adapted, too lean, too long a fast, or…some other factors) it could slow things down, but the reason it generally doesn’t slow things down is that it’s not actually a caloric restriction.

(David Brown) #5

first off all the “biggest loser” not working and people getting fat again is not a reflection on the regime they undertook. they all lose an insane amount of weight and most of them put it back on again. this isn’t because the diet was bad its purely down to lack of support after the show. when the fat is off its off. if you put it back on again then you’ve done something wrong.

a good example of this is a bodybuilder that consumes 5000 calories a day when bulking. when they diet they gradually reduce the calories to about 1800 before a competition. after the competition they dont start eating 5000 calories again as they have become metabolically adjusted to 1800. they increase their calories by a small amount per week.

as for fasting. its not a calories restriction diet. you supposed to consume your maintenance calories within your window

oh and dr fung is seen as one of the biggest frauds in the industry. he’s been accused and ousted a few times by expert’s. personally i follow Thomas Delauer.

#6

Dr Fung is a nephrologist who treats diabetics. Who sees him as a fraud and what is he accused of? And what has he been ousted from?

(David Brown) #7

sorry. my mistake. i meant dr berg…my brain is frazzled today looking after 3 kids and a crazy dog.

#8

ah, got it. Good luck :slight_smile:

Sorry for the derail @daddyoh! I think the main answer to your question is in the insulin: food restriction + high insulin is a completely different metabolic scenario than food restriction + low insulin.

(Doug) #9

Fasting definitely is almost always an overall caloric restriction, yes, depending on the time period one looks at.

The human body has a different hormone response to longer periods of not eating, versus just eating less calories day-by-day. Dr. Fung looked at several studies, and the average resting metabolism increased by 13% by 4 days of fasting. Higher levels of norepinephrin are said to account for this.

There is individual variation - many people do feel colder when fasting, and this is “turning down the thermostat,” trying to conserve energy.

(Jane) #10

Thanks for bringing this up as I question this also.

I have had both results!

Some fasts I have lost weight and kept it off after refeeding (> 5 lbs) so I reset my “setpoint” with fasting and did not lower my metabolism.

My last fast I immediately regained the few pounds I lost from fasting. So what happened to my metabolism on that fast? It was a pure water fast for 3 days so I obviously had to use my fat stores for energy, right?

I broke my fast with keto foods. I actually don’t know what I lost and regained since I fasted when I was travelling on business without access to a scale. I just know I weighed the same when I got home as when I left.

I think there are other factors here we aren’t measuring. The human body is a complex chemical plant (I am a chemical engineer so that is my perspective) and when I have different results in the output of my unit that I cannot explain with the data I have (i.e. no correlation) then I assume there is something going on I am not measuring and need new instrumentation. And that instrumentation may not even exist (quick home tests for insulin, autophagy).

(Eric - The patient needs to be patient!) #11

Thanks for clarifying. I listened to Dr. Berg podcast like twice and decided he was just selling stuff.

(Dan) #12

“oh and dr fung is seen as one of the biggest frauds in the industry. he’s been accused and ousted a few times by expert’s. personally i follow Thomas Delauer.”

Yes, always best to follow an internet celebrity type vs a doctor with tears of experience successfully treating diabetes and obesity.

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(Doug) #13

He meant Eric Berg, not Dr. Fung.

(Wendy) #14

I think we also need to realize that we don’t know everything involved in how the body does all the things it does. I am persuaded by the works I’ve read from Gary Taubes and also Dr Fung that the body decides how to spend the calories we give it due to hormonal reasons, mainly insulin, but I also believe that there is much more to learn about metabolism and even other factors that affect how we metabolize uniquely. Every time scientists or we, think we have figured it all out, we find out there is so much more for us to learn. The body is vastly complex.
I do fast (IF) and also choose to eat three meals a day sometimes. I feel that if I don’t, that I’m just cutting my calories each day and I’m not convinced that won’t come back to bite me later.
I’m all for N=1 experimenting. I also know some results might not show up for years. There are plenty of kids that were able to eat whatever in their youth only to find out as they aged that it wasn’t working any more. Seeds planted take time to grow and produce fruit. ( Or vegetables :slight_smile:)

#15

I have the exact opposite effect when I am fasting, I am so hot with spikes of overheating on a few occasions, I guess I am one of the not so many.