LCHF - Low Carb High Fat Diet Ver 2

[Dubber]

Resting is up by at least 10 bpm.

 

It is difficult to say how much it increased while on the bike, but I ride about 6 km/h slower than I used to before LCHF and my ave HR is about the same over a 72km ride.

 

During HIT on the wattbike I now push lower watts over a 90 min training session at a higher ave HR.

 

Max HR was 176. Since I started LCHF I've pushed it to 186 on a number of occasions. I'm 46 (age)

My maximum hasn't increases but certainly during rides my HR is about 5 beats faster for the same effort.  That said, I don't feel like I'm working harder despite the increased heart rate.  So all in all, its a good thing.  Higher heart rate for same effort - more blood flowing, meaning more oxygen etc.

[HBO]

 So all in all, its a good thing.  Higher heart rate for same effort - more blood flowing, meaning more oxygen etc.

 

But doesn't this mean that energy expenditure is also higher causing you to run out of energy quicker?

 

I haven't experienced this on the bike yet, but then my rides are all low intensity so-far.

 

During HIIT sessions on the wattbike I ran out of steam, but perhaps that is because my body hasn't fully adapted yet?

[jcza]

 So all in all, its a good thing.  Higher heart rate for same effort - more blood flowing, meaning more oxygen etc.

 

But doesn't this mean that energy expenditure is also higher causing you to run out of energy quicker?

 

I haven't experienced this on the bike yet, but then my rides are all low intensity so-far.

 

During HIIT sessions on the wattbike I ran out of steam, but perhaps that is because my body hasn't fully adapted yet?

 

 

I have the same question and it is still unanswered - what replaces muscle glycogen which is needed at high intensity when on LCHF? Cutting out carbs depletes glycogen so it makes sense that you will suffer from lack of steam. My own thinking is that carbs are required for high intensity. Live low carb but race carb. The journey continues.

 

Update -  http://lowcarbperformance.blogspot.com/2015/06/lets-measure.html

[Patchelicious]

I have the same question and it is still unanswered - what replaces muscle glycogen which is needed at high intensity when on LCHF? Cutting out carbs depletes glycogen so it makes sense that you will suffer from lack of steam. My own thinking is that carbs are required for high intensity. Live low carb but race carb. The journey continues.

 

Update -  http://lowcarbperformance.blogspot.com/2015/06/lets-measure.html

I agree and subscribe to the same thinking.

 

I suffer during higher intensity training due to lack of carbs, but thats ok and I allow it.

 

BUT for races I cannot suffer, so I munch some carbs. Right after race, back to LC.

[SimpleDom]

I have the same question and it is still unanswered - what replaces muscle glycogen which is needed at high intensity when on LCHF? Cutting out carbs depletes glycogen so it makes sense that you will suffer from lack of steam. My own thinking is that carbs are required for high intensity. Live low carb but race carb. The journey continues.

 

Update -  http://lowcarbperformance.blogspot.com/2015/06/lets-measure.html

 

So the science on this that I have read says that to some extent, keytones are used in place of glucose for muscles. The brain still needs glucose, so most of the glucose you produce from gluconeogenesis will be routed to the brain first. Creation of keytones is a more expensive process, so we don't really produce enough to run aerobic for any length of time. There was an experiment where the guys were given a keytone suppliment (Someone has created a process to extract these into a drinkable liquid, making them "free"), where they found that High Intensity performance equalled that fuelled on glucose, but for the rest of us that don't have access to "Free" keytones, the expense to create them is apparently the limitation.

 

So, I see a lot of hype around SuperStarch.... It apparently gives you the carbs with no insulin spike. So you still burn fat optimally, but once you're anerobic, you have a store of glucose (stored in cells as glycogen) to to access. The theory goes, since there is no insulin response, your blood glucose level is maintained for longer. I haven't tried this myself yet (SuperStarch is making it's way to me as we speak)....

 

Of course the thing we all do know is, by living LCFH, you gain metabolic efficiencies that mean you need glucose much later in your intensity curve (you burn fat for longer). For me, the difference was between 110 BPM HR on glucose to 170 BPM HR once fat adapted. Once I exceed 170 and have not fuelled with Carbs, the power loss is quick and brutal. If I lower intensity again, the recovery is very quick, and I'm able to keep going.

 

FAT burning needs oxygen. when there's not enough oxygen, you need loads of keytones or Glucose. There isn't another option (other that alcohol!) as far as I understand.

[jcza]

So the science on this that I have read says that to some extent, keytones are used in place of glucose for muscles. The brain still needs glucose, so most of the glucose you produce from gluconeogenesis will be routed to the brain first. Creation of keytones is a more expensive process, so we don't really produce enough to run aerobic for any length of time. There was an experiment where the guys were given a keytone suppliment (Someone has created a process to extract these into a drinkable liquid, making them "free"), where they found that High Intensity performance equalled that fuelled on glucose, but for the rest of us that don't have access to "Free" keytones, the expense to create them is apparently the limitation.

 

So, I see a lot of hype around SuperStarch.... It apparently gives you the carbs with no insulin spike. So you still burn fat optimally, but once you're anerobic, you have a store of glucose (stored in cells as glycogen) to to access. The theory goes, since there is no insulin response, your blood glucose level is maintained for longer. I haven't tried this myself yet (SuperStarch is making it's way to me as we speak)....

 

Of course the thing we all do know is, by living LCFH, you gain metabolic efficiencies that mean you need glucose much later in your intensity curve (you burn fat for longer). For me, the difference was between 110 BPM HR on glucose to 170 BPM HR once fat adapted. Once I exceed 170 and have not fuelled with Carbs, the power loss is quick and brutal. If I lower intensity again, the recovery is very quick, and I'm able to keep going.

 

FAT burning needs oxygen. when there's not enough oxygen, you need loads of keytones or Glucose. There isn't another option (other that alcohol!) as far as I understand.

 

The way I understand it is that ketones will fuel the brain instead of blood/liver glucose. This still leaves me wondering where the muscle glycogen will come from. From what I read you cannot replenish muscle glycogen on the go (even when racing carb). Best we can hope for is to slow depletion. I have tried superstarch and it did nothing for me. Also have a read up about insulin response during exercise, it does not spike contrary to popular belief. 

[jcza]

In intense exercise (>80% VO(2max)), unlike at lesser intensities, glucose is the exclusive muscle fuel. It must be mobilized from muscle and liver glycogen in both the fed and fasted states. Therefore, regulation of glucose production (GP) and glucose utilization (GU) have to be different from exercise at <60% VO(2max), in which it is established that the portal glucagon-to-insulin ratio causes the less than or equal to twofold increase in GP. GU is subject to complex regulation by insulin, plasma glucose, alternate substrates, other humoral factors, and muscle factors.........

 

Rest is here - http://www.ncbi.nlm.nih.gov/pubmed/11815492

[NotSoBigBen]

I am not too fussed about the science of all of this and live my own version of the LCHF lifestyle (no crazy stuff) and am purely looking at the health benefits for me (feel better and keeping a steady 'good' weight)

 

I am not that worried about whether it affects my ability to ride 'hard' as the above benefits are more important to me but having said that I also do the race on carb drinks, energy gels, bananas whatever it takes and then immediately I stop I go back to what I was doing before (don't bother with recovery drinks or eating something straight away or anything)

 

On my local courses that I ride often I am riding as well as I ever have in my youth but that may be more down to the weight loss than anything else.

 

That is anyway my take on it and I am sure that those wanting still to 'race' competitively will see it differently. I don't know where my body gets it's energy from but it seems to manage OK

[SimpleDom]

The way I understand it is that ketones will fuel the brain instead of blood/liver glucose. This still leaves me wondering where the muscle glycogen will come from. From what I read you cannot replenish muscle glycogen on the go (even when racing carb). Best we can hope for is to slow depletion. I have tried superstarch and it did nothing for me. Also have a read up about insulin response during exercise, it does not spike contrary to popular belief. 

 

Yes, the brain can use keytones, but apparently preference is given to the brain for any available glucose. What I mean is, you can't make enough for your muscles from protein....

 

I understand the replenishment thing the same way. We can only really hope to be more metabolically efficient to slow down the glycogen use.

 

Did you use the SuperStarch pre-race? I can't wait to try the stuff. I wasn't planning on carrying it on the bike, but rather using it 30 mins before the race.

 

My current crossover is a 87% of my max HR (measured in the V02 Max test). I'm not going to get more efficient, so if I want to improve my racing, I'll need to fuel with carbs before hand.

 

The LCHF guy that won the iron man a while back seemed to start with some more carb in the few days leading up to the event, and then smashed all the coke he could find on the day. Seemed to work for him.

 

In summary, same sentiment as you. Race on carbs.... 

[jcza]

Update on Kalahari Challenge sufferfest (no carbs) - http://lowcarbperformance.blogspot.com/2015/06/kalahari-challenge-botswana.html

[HBO]

Update on Kalahari Challenge sufferfest (no carbs) - http://lowcarbperformance.blogspot.com/2015/06/kalahari-challenge-botswana.html

Well, hats off to you for staying disciplined to your goals and not to succumbed to the "carb treats" at the water points, although you knew it will certainly boost your energy levels.

 

I follow your posts with keen interest, since I'm now on lchf for 3 months and still don't have any power to do HIIT. No problem to go steady or even tempo for 3h30 on the road, but during HIIT (on the wattbike) I can't maintain the same effort levels- not even remotely- than prior to lchf.

 

Good luck.

Edited July 3, 2015 by HBO

[davetapson]

The way I understand it is that ketones will fuel the brain instead of blood/liver glucose. This still leaves me wondering where the muscle glycogen will come from. From what I read you cannot replenish muscle glycogen on the go (even when racing carb). Best we can hope for is to slow depletion. I have tried superstarch and it did nothing for me. Also have a read up about insulin response during exercise, it does not spike contrary to popular belief. 

 

Hi jc

 

My understanding is that the liver produces glucose via a process called gluconeogensis (probably means 'makes glucose' in latin )

 

I remember reading a study that measured blood glucose in endurance runners and the bottom line was that the liver keeps the blood glucose pretty constant even if no glucose is being ingested.  In the study I think they were looking at 100 milers and the blood glucose remained pretty constant.

 

I think the issue with cycling esp mountain biking is can the liver produce enough glucose to maintain high intensity exercise.  HTOne used to say that he believed it was possible if you trained / adapted right.  

 

I never quite got there - which is not to say that it is not possible...

[jcza]

Hi jc

 

My understanding is that the liver produces glucose via a process called gluconeogensis (probably means 'makes glucose' in latin )

 

I remember reading a study that measured blood glucose in endurance runners and the bottom line was that the liver keeps the blood glucose pretty constant even if no glucose is being ingested.  In the study I think they were looking at 100 milers and the blood glucose remained pretty constant.

 

I think the issue with cycling esp mountain biking is can the liver produce enough glucose to maintain high intensity exercise.  HTOne used to say that he believed it was possible if you trained / adapted right.  

 

I never quite got there - which is not to say that it is not possible...

 

Dave my understanding is that proteins must be broken down into their constituent amino acids before it can be used as fuel. One of these amino acids, alanine is then released into the bloodstream and is converted into glucose by the liver by gluconeogenesis . However the problem is the conversion rate which is around 4gr per hour while one needs 3gr of glucose per minute at high intensity. 

[davetapson]

3g/min!!  Hectic...

 

Out of interest what of fats (in any form, incl ketones) being used as a substrate for glyconeogenesis?

 

Will try and have a google when I get home.

[deanbean]

3g/min!! Hectic...

 

Out of interest what of fats (in any form, incl ketones) being used as a substrate for glyconeogenesis?

 

Will try and have a google when I get home.

Don't you remember your Biochem Dave ;-)

[Dubber]

 So all in all, its a good thing.  Higher heart rate for same effort - more blood flowing, meaning more oxygen etc.

 

But doesn't this mean that energy expenditure is also higher causing you to run out of energy quicker?

 

I haven't experienced this on the bike yet, but then my rides are all low intensity so-far.

 

During HIIT sessions on the wattbike I ran out of steam, but perhaps that is because my body hasn't fully adapted yet?

Well, that is the paradox right there.  If you are running on glucose, yes, you have a limit which you hit - normally around 90 to 120 minutes. But burning fat, your reserves are much greater so you can run 'hotter' for a much longer period without bonking.  That's my experience anyway.  (I did 100 miler without any carbs until around the 120km mark.  At that point I had an energy drink and ate some of the goodies at the refreshment table).