IF leading to low metabolic rate?

(Wenchie) #1

I had my @Groversaurus over for the weekend and for that sort of broke with my habit of daily IF. As a result I gained some weight that is still a bit persistent, even though I am back to IF. This observation lead to us discussing if IF fasting slows your metabolism down as I never have much more than 1000 kcal a day normally. So did I ruin my metabolism?

Don’t get me wrong! I am not starving myself!!! I listen to my body and I am not hungry!

I was under the impression that as a fat person I would “fill” the missing calories for my body to keep up its metabolism from my body fat and the crispy cream I never had in my life :stuck_out_tongue_winking_eye: I thought I understood @richard by assuming having about 1000 kcal a day would be fine because my bodyfat keeps my metabolism going good.

So why do I gain significant weight if I just eat that little more (btw still being under my calculated BMR rate?)

Please give me some science you lovely people :heart_eyes:

(Richard Morris) #2

Great. That’s the way. Let your body determine what it’s metabolic rate will be. It will be different for all of us, based on our unique genetic inheritance and environment. 1000 kCal for one person may be too much, and 3000 for another may be not enough [although those people would be extreme outliers].

If, as you reduce calories, you become lethargic and hungry then it is a reasonable assumption that your body is not making up the difference from body fat. The biochemical mechanism is that when insulin is high, your body fat contributes less energy to your body’s calculus.

It is also true that people who don’t have a lot of body fat become hungry and lethargic when they reduce their calories. For the same reason - their body fat is not contributing.

If you gain weight when you eat more than a set amount of calories then that is because it is above the metabolic rate your body has decided to run at that day.

Some people when their bodies have more energy they engage in wasteful uses of energy to burn it off - like heating the body, or ramping up the immune response, or even just involntary twitching (eg: crazy legs). So for them their metabolic rate increases when they eat more energy.

For other people just a little more energy than they need, and their bodies store it eagerly. I suspect that your basal level of insulin will determine where you fit on that continuum, because we know that insulin is a signal to hold energy in fat tissue and your basal level is how low you can usually get that.

Someone who has a normally very low level, or who has an endocrine system that is able to be very responsive based on food stimulants - likely sees their metabolic rate increase much more when they have more energy in the diet.

The biggest loser followup study showed that people who reduced their caloric intake beyond normal fueling signals (ie: eating less when they were still hungry) slowed their metabolism dramatically, and as long as they kept restricting intake it stayed slowed till the end of the study 6 years later.

I would like to see what happened to the BMR of any participants who switched to a low carb, fat to satiety diet … I suspect it would go back to their starting value. But Kevin Hall definitely doesn’t want to do that study.

(Wenchie) #3

Wow, thank you @richard for all this information. It was such a good explanation.

Well I am not aware of my actual BMR rate… my scale says 1920 kcal but thats massive amount of food. I eat fully keto and am not diabetic or prediabetic so I was hoping my metabolism is not too deranged. :flushed:

So as I don’t plan on quitting this WOE for the rest of my life I was still hoping that as long as I don’t totaly overeat on keto I will not gain easily when eating a reasonable amount of food within the right macros. But seemingly even 2 meals a day will actually let me gain back weight. Thats a bit of a shame :joy::joy: but still ok I guess.

I’am also asking as there is hardly any good information for us Germanese people in our language, so many people I talk to about Keto can not read up things themselves or listen to your lifechanging potcasts down to not speaking English well, so I try to not pass on false information to them. The only german written book is Bruce Fives book about the Keto principle, that more or less says as long as you eat good fat you will loose (that just been proven wrong in my n=1 case)

So please let me ask again, just to make sure I got it right: As an obese person with looots of bodyfat and being totally fat adapted- will my body slow down my metabolism when I reduce the calorie intake? Or will it maintain its normal activ state ans simply take whats needed from my body fat? Or will reducing my calorie intake slow down my metabolism automatically?

Thank you so much for taking the time to answer! It means a lot getting this great information from you!

(Richard Morris) #4

Your body’s energy homeostasis will make that calculus. We can certainly take a guess at what will happen based on your fasted insulin.

If your insulin is above 13 mIU/L then energy from body fat is not going to be part of the calculus - the first law of thermodynamics will require your metabolic rate to slow in response and your body will try to find other sources of energy (making your hungry to give you the hint, even burning lean mass to make up the energy shortfall).

In that state your body will certainly try to lower insulin production, when it can get that low enough then you will draw down some body fat - but of course your metabolic rate will still be slow, and you’ll likely remain lethargic and hungry.

If however your fasted insulin is down below 6 mIU/l then as you reduce calories in, you’ll likely make up the shortfall from body fat.

So I’m afraid the answer is “It depends”

(Wenchie) #5

I see! Well that explanation helps a lot actually. Thank you so much :blush::heart_eyes_cat:

(Jim Russell) #6

Richard,

Other than fasting for 12 hours or so before an insulin test, are there any other caveats? I think I remember you mentioning that you also shouldn’t drink caffeine before an insulin test. Is that correct? For how many hours must we not drink caffeine?

Thanks.

(What The Fast?!) #7

Ooh, interesting!! That endocrine system thing! I’ve been suspecting that my endocrine system (this is the digestive system, I think?) is not responsive, even though my insulin levels are low…so I bet your hypothesis works in reverse. If my endocrine system is slow, it doesn’t react quickly and my metabolic rate is decreased (or stagnant).