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-   -   Ketosis, metabolism, refeeds (http://forums.lylemcdonald.com//showthread.php?t=32241)

TravisGM 08-17-2016 01:10 PM

Ketosis, metabolism, refeeds
 
Hello all! I understand there is a lot of content in here about ketosis and refeeds but I want to attempt to clarify this idea that refeeds help "boost" your metabolism back up.




McDonald states, "In general, short refeeds, lasting from 5 to 24 hours were used every so often while dieting. Iíve tried them all .... The question is whether or not those programs were optimal. In my opinion, they arenít for several reasons.

One of the factors Iíve been considering to a great degree has to do with the length of the overfeeding period. While itís true that 5 (or 12 or 24) hours of concentrated overfeeding will raise leptin, the more important question is whether thatís sufficient to Ďtellí the brain that youíre fed. While data (especially in humans) is nonexistent, my hunch is no.

Thereís a lag time of several days between the drop in leptin and the drop in metabolic rate (nervous system output) for example; Iíd be surprised if a mere 12 or 24 hours was sufficient to reverse this. Rather, Iíd expect it to take a similar amount of time for the reversal to occur ...

Now, this isnít to say that short carb-loads/refeeds arenít of benefit. They refill glycogen, turn off catabolism and maybe induce an anabolic response to boot. They also let you eat some of the crap youíre really craving which helps psychologically. But I doubt they are sufficient to affect metabolism very much. Instead, a longer refeed is necessary. The drawback, of course, is that longer refeeds have a tendency to put too much bodyfat back on which goes agains the entire goal of dieting."

So can we clarify whether refeeds actually boost the metabolism or not? They have obvious benefits (as he stated), but the main concern is metabolism manipulation. Anyone have any science to back up his claim (or refute it)?

tellurium 08-18-2016 03:16 AM

I'm new to the board but I'm 99% sure this has been answered elsewhere on the forum, many times.

TravisGM 08-18-2016 09:27 AM

Quote:

Originally Posted by tellurium (Post 294614)
I'm new to the board but I'm 99% sure this has been answered elsewhere on the forum, many times.



That's interesting cause so far I haven't found it...

PhysiologyIsPhun 09-08-2016 02:27 PM

From my understanding of leptin, the small refeeds will NOT boost metabolism. It seems that a minimum of one week of >=150g of carbohydrate consumption is needed to increase leptin, and up to a full 14 days to normalize it completely. And even at this point, leptin will still be slightly downregulated unless you gain all the fat back you lost. Leptin plays a large role in metabolism, so replace everytime I used "leptin" with "metabolism", and you have your answer.

lylemcdonald 09-08-2016 04:02 PM

Quote:

Originally Posted by PhysiologyIsPhun (Post 295345)
From my understanding of leptin, the small refeeds will NOT boost metabolism. It seems that a minimum of one week of >=150g of carbohydrate consumption is needed to increase leptin, and up to a full 14 days to normalize it completely. And even at this point, leptin will still be slightly downregulated unless you gain all the fat back you lost. Leptin plays a large role in metabolism, so replace everytime I used "leptin" with "metabolism", and you have your answer.

Nope. Leptin will go up in 5 hours of overfeeding. The question is whether or not it can send a useful signal to the brain. The answer is most likely no

Even 2 days of refeeding can.

Myles.Buckley 09-08-2016 11:07 PM

a bit of background for the folks:

High levels of circulating fatty acids in the blood can quickly downregulate (impair) the leptin transport at the blood-brain barrier.

Lowering the levels of fatty acids in the blood can allow the blood-brain leptin transport to recover, but the up-regulation process is MUCH slower than the down regulation.

I doubt even a week will meaningfully improve leptin brain signalling in most folks.

TravisGM 10-19-2016 05:55 PM

Thanks all. I think the answer is overall, no. It doesn't seem to be a noticeable difference.

lylemcdonald 10-20-2016 08:13 AM

Quote:

Originally Posted by PhysiologyIsPhun (Post 295345)
From my understanding of leptin, the small refeeds will NOT boost metabolism. It seems that a minimum of one week of >=150g of carbohydrate consumption is needed to increase leptin, and up to a full 14 days to normalize it completely. And even at this point, leptin will still be slightly downregulated unless you gain all the fat back you lost. Leptin plays a large role in metabolism, so replace everytime I used "leptin" with "metabolism", and you have your answer.

Noi no no, your screen name is hysterical because you don't understand squat about physiology

Leptin will go up within 5 hours of high calories/carbs

The issue is whether or not the brain will get enough of a signal to reverse anything

That takes 1-2 days of maintenance calories depending on a host of factors.

A full diet break is different

lylemcdonald 10-20-2016 08:14 AM

Quote:

Originally Posted by Myles.Buckley (Post 295354)
a bit of background for the folks:

High levels of circulating fatty acids in the blood can quickly downregulate (impair) the leptin transport at the blood-brain barrier.

Lowering the levels of fatty acids in the blood can allow the blood-brain leptin transport to recover, but the up-regulation process is MUCH slower than the down regulation.

I doubt even a week will meaningfully improve leptin brain signalling in most folks.

You're utterly completely wrong but that's ok.

TravisGM 11-13-2016 06:55 PM

Quote:

Originally Posted by lylemcdonald (Post 296718)
You're utterly completely wrong but that's ok.

So going back to my original question, are you suggesting that 1-2 days of eating maintenance calories will in fact help your metabolism normalize? Just trying to clear it up.


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