Enough carbs to fuel your brain...........

[LittleGreyCat]

This bit of advice about the minimum amount of carbs to eat each day continues to puzzle me.

Presumably if you are on a settled diet with steady weight with a settled exercise regime and everything else stable, then you can assume that your consumption of various foodstuffs will generally go mainly directly to fuelling your body.
Well, can you?
Nobody says if you just keep the nutrients disolved in your blood, or reserved in your gut for slow release, between meals.
Perhaps they go into storage (fat) in the couple of hours after your meal and. then are released again over the next couple of hours before your next meal?
In fact, isn't this the whole point of insulin?
So somewhere in your body you may be breaking down fat to provide energy.

Also, if you are on a reduced calorie diet and are losing weight then you must be meeting at least some of your daily energy needs by breaking down body fat.

If you don't exercise as much for a few days then as I understand it you start to lose muscle mass - which is why to maintain/increase fitness you have to exercise every 2 or 3 days or you lose the benefit.
Which means that probably quite often you are breaking down protein to meet your energy needs (or to convert it into fat).

O.K. - the mechanism for moving fat/protein to and from your own body tissues is different from absorbing and breaking down external nutrients but why is this 'minimum carb for the brain' thing such a big deal?

As far as I know the hunter/gatherers didn't have a regular daily diet.
Some days (weeks, months) they lived mainly on plants but in the time of plenty (spring/summer probably) when there was a lot of new game available they would probably eat a high proportion of meat, and gorge on a kill before it went bad or attracted bigger and nastier meat eaters.
So they should have adapted to meeting all their energy needs from protein and fats, at least for part of the year.

What is it that makes us as omnivores carb dependant?

Is it just that long term very low carbing produces more waste products than the low overhead processing of carbs for energy and this can increase the load on our internal organs, especially kidneys?

Or is it just that someone has calculated the average carbohydrate consumption of the human brain over a day and decided that it is a good idea to fuel the brain directly with cabs without really spelling out why?

Oh, and on the topic of 'correlation does not imply causation' if you are eating the recommended minimum carbs per day (again presumably split over 3 or more meals or it makes even less sense) what are the guarantees that the energy needs of the brain are met directly by the carbohydrates consumed and not at least partially by the breakdown of proteins and fats?

Oh, and if the real issue is the waste products created by breaking down fats and proteins, why is this O.K. to fuel the muscles and other organs but not the brain?

Oh, and if you are planning to do a lot of thinking (like writing a long post) should you as a precaution neck down a few extra carbs to enable you to get to the end without flagging or losing the plot? :shock:

Cheers

LGC

 

[phoenix]

This bit of advice about the minimum amount of carbs to eat each day continues to puzzle me.

Presumably if you are on a settled diet with steady weight with a settled exercise regime and everything else stable, then you can assume that your consumption of various foodstuffs will generally go mainly directly to fuelling your body.
Well, can you?
Nobody says if you just keep the nutrients disolved in your blood, or reserved in your gut for slow release, between meals.
Perhaps they go into storage (fat) in the couple of hours after your meal and. then are released again over the next couple of hours before your next meal?
In fact, isn't this the whole point of insulin?
So somewhere in your body you may be breaking down fat to provide energy.

Help!
How about this

In non-obese non-diabetic subjects, after ingestion of a 100 g glucose load, about 40 g
glucose are oxidized within 3 h of ingestion, whereas about 50 g are stored as glycogen
(Felber et af. 1983), the remaining 10 g being not yet absorbed. The actual amount of
glycogen synthesized might be slightly underestimated due to an incomplete suppression
of endogenous glucose production. During the 3 h period after a 100 g glucose load,
glucose, lipid and protein oxidation respectively accounted for 60, 25 and 15% of the
energy expenditure

So some is absorbed, some stored and some burned .

http://journals.cambridge.org/download. ... 80e4f96db5

Also, if you are on a reduced calorie diet and are losing weight then you must be meeting at least some of your daily energy needs by breaking down body fat.
Yes, you are. This is also true when you are weight stable; people use fat as a fuel all the time , someone exercising at about 65% heart rate for a prolonged period is utilising 40-60% fat
http://science.howstuffworks.com/enviro ... -cell2.htm
http://en.wikipedia.org/wiki/Aerobic_exercise

If you don't exercise as much for a few days then as I understand it you start to lose muscle mass - which is why to maintain/increase fitness you have to exercise every 2 or 3 days or you lose the benefit.
Which means that probably quite often you are breaking down protein to meet your energy needs (or to convert it into fat).
conversion of protein to fat inefficient (see the how stuff works link)
A main purpose of protein is to build and repair the body . If not enough fuel is supplied from dietary sources then the body will use muscle protein for energy so one of the problems with weight loss is indeed muscle loss. This can lead to sarcopenia
Sheri Colberg writes about this in relationship to weight loss and diabetes
http://www.diabetesincontrol.com/articl ... t-exercise


O.K. - the mechanism for moving fat/protein to and from your own body tissues is different from absorbing and breaking down external nutrients but why is this 'minimum carb for the brain' thing such a big deal?

Give up at this point (have to do the ironing) I can give you the reference as to how the figure was reached and a paper that describes mainstream objections to LC/ketogenic diets l (read it, I'm not going to argue for or against!)
http://www.nap.edu/openbook.php?record_ ... 0&page=285
http://dro.deakin.edu.au/eserv/DU:30008 ... s-2003.pdf



LGC

 

[IanD]

The quick answer must be that as long as our blood glucose is in the non-diabetic range (4-5 or above) our brain must be adequately fuelled regardless of what we eat.

I read about the need for BG from carbs in the DUK "Healthy Eating" booklet. I phoned them more than a year ago for references, & they promised to send details .....

Why is carbohydrate important?
All carbohydrate is converted into glucose and will have an impact on blood glucose levels. As this is the case, some people
with diabetes wonder if it would be better not to have any carbohydrate in their diet to keep their glucose levels under control. This is not recommended as:
• glucose from carbohydrate is essential to the body, especially the brain
• high fibre carbohydrates, such as wholegrains and fruit, also play an important role in the health of the gut
• some carbohydrates may help you to feel fuller for longer after eating.

Obviously there is some research out there that distinguishes blood glucose from carbohydrate from blood glucose from other foods ....

 

[borofergie]

What is it that makes us as omnivores carb dependant?

Or is it just that someone has calculated the average carbohydrate consumption of the human brain over a day and decided that it is a good idea to fuel the brain directly with cabs without really spelling out why?

Mammals are not carb dependent. You can easily survive (and thrive) on a zero-carbohydrate diet. Carbohydrates are not an essential macronutrient.

On a high carb diet your central nervous system uses about 100 to 120g of glucose per day. If you eat at least 120g of carbohydrate a day, your CNS will get first call on the carbohydrates (the so called "selfish brain" theory).

On less than 120g a day, your CNS will fuel itself from gluconeogenesis (breaking down protein and fat to make glucose) and from ketones (a bi-product of fat burning).

On a zero-carb diet, your CNS switches to getting 75% of its energy from ketones. It still requires 25-30g of glucose, but that can all be manufactured from gluconeogenesis. In principal, you don't need any carbs to function properly.

The "enough carbs to fuel your brain" thing is dogmatic nonsense that dieticians (and unfortunately sometimes Doctors) splurt out because they don't know what they are talking about. Treat anyone who tells you that you need to eat a certain amount of carbohydrate to stay alive with a great deal of suspicion.

 

[borofergie]

Why is carbohydrate important?
All carbohydrate is converted into glucose and will have an impact on blood glucose levels. As this is the case, some people
with diabetes wonder if it would be better not to have any carbohydrate in their diet to keep their glucose levels under control. This is not recommended as:
• glucose from carbohydrate is essential to the body, especially the brain
• high fibre carbohydrates, such as wholegrains and fruit, also play an important role in the health of the gut
• some carbohydrates may help you to feel fuller for longer after eating.

This goes just goes to demonstrate that DUK to understand what they are talking about. In fact I'd dispute all three of those points.

1)Your brain does require 25g of glucose a day, but it doesn't need to come from dietary carbohydrate.
2) No they aren't, you can easily get enough fibre from green vegetables
3) Carbohydrates are generally accepted to be less satieating than fat or protein

 

[Patch]

:think:

 

[LittleGreyCat]

<snip>

O.K. - the mechanism for moving fat/protein to and from your own body tissues is different from absorbing and breaking down external nutrients but why is this 'minimum carb for the brain' thing such a big deal?

Give up at this point (have to do the ironing) I can give you the reference as to how the figure was reached and a paper that describes mainstream objections to LC/ketogenic diets l (read it, I'm not going to argue for or against!)
http://www.nap.edu/openbook.php?record_ ... 0&page=285
http://dro.deakin.edu.au/eserv/DU:30008 ... s-2003.pdf

Well the second reference doesn't beat about the bush!

Complications such as heart arrhythmias, cardiac
contractile function impairment, sudden death, osteoporosis, kidney damage, increased cancer risk, impairment of
physical activity and lipid abnormalities can all be linked to long-term restriction of carbohydrates in the diet. The
need to further explore and communicate the untoward side-effects of low-carbohydrate diets should be an
important public health message from nutrition professionals.

If I suffered from both sudden death and impairment of physical activity I would be round to the doctor's straight away! :lol:

Run out of time to read it all at present but as far as I have got it seems fairly light on the logical proofs. More a 'pick a statistic and explain how it must support your chosen theory'.
The main thrust seems to be against low carb diets as a method of weight conttrol.

The main message is that there don't seem to be any long term studies of low carbing with relation to diabetic BG control.
Once you get past the propoganda bits there is a lot of interesting information, again mainly stating that not a lot is known from long term studies.

Common adverse events attributed to the diet included dehydration, gastrointestinal symptoms, hypoglycaemia, as well as carnitine and vitamin deficiencies.

So drinking plenty of water, and taking yeast tablets, and you are mainly left with hypoglaecemia.
Now it may just be me but aren't we sort of looking for ways to get our BG down?

Also, not clear indication of how low carb you need to go to enter permanent ketosis

Currently, there is no consensus as to what is the absolute cut-off limit for the maximal amount of carbohydrate intake necessary to induce ketosis. Induction of ketosis is likely to vary on an individual basis, however, intakes in the range of 50-100g of carbohydrate a day are generally reported - typically representing less than 20% of energy from carbohydrate.

So possibly if you are on 60g-80g of carbs per day you are not in ketosis.
I haven't checked (not sure if the usual blood tests will show this) but apart from pee sticks how do you tell if you are in ketosis or dipping in and out?
Whatever, the "bummer" message seems to be tightly focussed around people who maintain permanent ketosis.

Comparison of a range of popular diets revealed that lowcarbohydrate diets (defined as less then 30% of energy from carbohydrate) fared worse in terms of dietary adequacy (as defined by the amount of inclusion of the five major foods groups and alignment with the U.S. Dietary Guidelines)

So no study of actual bad effects from the diet - obvious nutritional deficiencies shown by symptoms - but just that the diet does not conform to current (then) guidelines which is a sort of circular argument.

Gotta go now (can't blame the ironing) but this does seem to argue from a chosen premise instead of taking an disinterested look at all the facts and figures.

As I said above, it also seems to be mainly a diatribe agaist Atkins style diets and so far doesn't consider reduced carbs for BG control in diabetics where the risk factors are somewhat different.

Cheers

LGC

 

[borofergie]

Common adverse events attributed to the diet included dehydration, gastrointestinal symptoms, hypoglycaemia, as well as carnitine and vitamin deficiencies.

So drinking plenty of water, and taking yeast tablets, and you are mainly left with hypoglaecemia.
Now it may just be me but aren't we sort of looking for ways to get our BG down?

The hypoglycemia thing is a strange thing to write, since ketosis is a glucose sparing mechanism that exists to prevent hypocglycemia under starvation conditions. Think about it, ketosis involves switching your whole metabolism to run off of fat and ketones, with the expception of one teaspoon of sugar that you need to fuel your brain (and which you can manyfacture from fat and protein).

I, and many other diabetics, use ketosis because it gives us tight BG control. My BG doesn't really go up, it doesn't really go down. It just stays between 5 and 6 mmol/l all day.

If I starved myself for a month, I'd lose some body fat and some muscle mass, but wouldn't go into a diabetic coma...

 

[Sid Bonkers]

Mammals are not carb dependent. You can easily survive (and thrive) on a zero-carbohydrate diet. Carbohydrates are not an essential macronutrient.

If that statement is true why is it that low carbers feel the need to take so many supplements?

Taken from the "Informed choices - downsides of LCHF?" thread this is a list of the supplements members say they take.

Fibre Supplements
Omega 3
Vit B1
Vit D3
Folic Acid
Vit B12
Calcium
Vit D
Fish Oils
Magnesium
Zinc
Q10 (not heard of this one before?)

If carbs are not essential why so many supplements?

 

[IanD]

Thanks, Phoenix, for finding the relevant papers.

All diets considered were hypoenergetic - intended to be weight reducing. Energy requirements from food would be inadequate, & some problems resulted from that. Advice is given on avoiding deficiencies & potential problems. (see below)

Type of diet -------Total kJ (kcal) # Fat g (% E)# CHO g (% E) # Protein g (% E) #
Typical American ---9250 (2200) # 85 (35) # 275 (50) # 82.5 (15)
HF LC ------------------5950 (1414) # 94 (60) # 35 (10) # 105 (30)
Moderate-fat, balanced nutrient reduction
------------------------ 6100 (1450) # 40 (25) # 218 (60) # 54 (15)
Low- and VL-fat ----6100 (1450) # 16-24 (10-15) #235-271 (65-75) # 54-72 (15-20)

There are a lot of 'may be' in the text, with health problems being attributed to LCHF but could be due to diet deficiencies of various kinds. In effect, if you are on a diet, your problems are caused by the diet. But we are aware of our bodies & specific problems, & can make adjustments & the following advice towards the end of the paper makes helpful suggestions:

Advice should be given to an individual following a
low-carbohydrate diet to help avoid some of the potential
metabolic consequences known to be associated with this
diet. For example, advice would include: to increase the
intake of water to help prevent dehydration; ensure an
adequate intake of fibre from non-starch containing foods;
and to consume an adequate amount of calcium either
from the consumption of low-fat dairy products, canned
fish with bones or from the use of supplements. The use
of a general multivitamin formulation would also seem
prudent in light of the array of vitamin and mineral
deficiencies that may potentially exist. Certainly those
with a history of heart problems should be strongly
dissuaded from restricting carbohydrates whilst undertaking
vigorous exercise due to potential cardiac abnormalities
associated with ketogenic diets.

The focus of the paper is on weight loss, rather than diabetes control, though the effect on blood glucose is considered incidentally. The paper is 10 years old, & recent research would not appear to have substantiated "the potential negative
health aspects."

Conclusions
In the face of the rising tide of obesity in developed
countries, the lure of easily attainable weight loss by
following a low-carbohydrate diet is certainly appealing,
yet little discussion is given to the potential negative
health aspects potentially associated with this type of
dieting regime. When health professionals speak of low carbohydrate
diets they often repeat the message of lack
of concentration, kidney problems and bad breath and
often say ‘low-carbohydrate diets can be dangerous’.
This does little to deter people in the quest for weight loss
and there is the commonly held belief that ‘As long as I
lose weight I don’t care what I have to do.’ By delivering
a stronger message in the future and addressing such
serious potential health aspects to low-carbohydrate diets
such as potential cardiac complications, osteoporosis,
muscle loss and possibly insulin resistance, people are
better able to make informed choices based on the latest
scientific thinking about the risks associated with popular
dietary practices such as low-carbohydrate diets. Future
studies are certainly warranted, especially in the
examining of the long-term efficacy of the use of low carbohydrate
diets and how much this type of dieting
pattern may alter an individuals perception of foods and
food choices well into the future.

 

[borofergie]

If that statement is true why is it that low carbers feel the need to take so many supplements?

Another crass generalisation. The only supplement that I take is Vitamin D. I eat more leafy green vegetables on a low-carb diet than I ever did on a "regular" diet.

The things that I don't eat - grains and sugar - are among the least nutritionally dense foods. Try comparing the micronutrient content of a plate of spinach and brocolli with a plate of "healthy wholegrains".

If carbs are not essential why so many supplements?

Carbs are macronutrients. Vitamins are micronutrients.

Some people eat a "low-saturated fat diet" and also take multi-vitamin pills. Does that prove that "saturated fat" is an essential micronutrient?

 

[librarising]

Sid Bonkers wrote
why is it that low carbers feel the need to take so many supplements?

Taken from the "Informed choices - downsides of LCHF?" thread this is a list of the supplements members say they take.

Fibre Supplements
Omega 3
Vit B1
Vit D3
Folic Acid
Vit B12
Calcium
Vit D
Fish Oils
Magnesium
Zinc
Q10 (not heard of this one before?)

When you say 'low-carbers' do you mean all low carbers, or diabetic low-carbers whose health has obviously broken down in some way, and for some cause ?

Perhaps it would be better to ask whether the people who take these supplements would take them even if low-carbing was not seen as a necessary response to their health problem.

The wider I read, the more I hear doctors talking of general vitamin/ element deficiency in the general population.
No or low symptoms doesn't mean the problem may not be there. Most chickens come home to roost, sadly.

As far as I'm aware, being a diabetic means my endocrinal system is dysfunctional/broken/in a bad way/up s**t creek without a paddle.

Q10 is something you don't want to be short of, and I would advise ALL statin users to supplement with this, as statins inhibit it's production, and reduce the synthesis of vitamin D.

Geoff

 

[Dillinger]

Sid Bonkers wrote
why is it that low carbers feel the need to take so many supplements?

Taken from the "Informed choices - downsides of LCHF?" thread this is a list of the supplements members say they take.

Fibre Supplements
Omega 3
Vit B1
Vit D3
Folic Acid
Vit B12
Calcium
Vit D
Fish Oils
Magnesium
Zinc
Q10 (not heard of this one before?)

Hi,

Let's have a look at those - I take some of them but not all.

Fibre Supplements - reluctantly I take these, roughage appears to be necessary and is admittedly difficult to get low carbing
Omega 3 - meant to be good for heart health; one of the key diabetic risks. Not associated with dietary deficiency.
Vit B1 - there is evidence that a large number of diabetics are deficient in this. Not associated with dietary deficiency.
Vit D3 - these is evidence that a large number of the population are deficient in this. Not associated with with dietary deficit.
Folic Acid - don't know about this
Vit B12 - metformin depletes your B12 levels therefore anyone on it is sensible to take this. Not associated with dietary deficit.
Calcium - don't know about this
Vit D - as above
Fish Oils - meant to be good for heart health; one of the key diabetic risks. Food source is lovely low carb fish.
Magnesium - meant to help with reducing blood pressure - a key risk for all diabetics.
Zinc - don't know about this, but oysters red meat and poultry are all zinc rich so again like fish oil low carbers shouldn't be deficient.
Q10 (not heard of this one before?) - statins deplete this, if you're on a statin you should take Q10 supplements.

So, most of those are dealing with recognised diabetes related deficiencies ; the B1 in particular and not dietary deficiency.

Here's a good short letter in the American Journal of Clinical Nutrition

http://www.ajcn.org/content/75/5/951.2.full

And in particular here's the full list of human essential nutrients (Note the absence of specific carbohydrates from this list.)

"The currently established human essential nutrients are water, energy, amino acids (histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine), essential fatty acids (linoleic and α-linolenic acids), vitamins (ascorbic acid, vitamin A, vitamin D, vitamin E, vitamin K, thiamine, riboflavin, niacin, vitamin B-6, pantothenic acid, folic acid, biotin, and vitamin B-12), minerals (calcium, phosphorus, magnesium, and iron), trace minerals (zinc, copper, manganese, iodine, selenium, molybdenum, and chromium), electrolytes (sodium, potassium, and chloride), and ultratrace minerals (4)."

Dillinger

 

[LittleGreyCat]

Err...yeah.
I am quite low carb (I don't carb count) but I don't take suppplements.
Perhaps I should, but I seem to be doing O.K. at the moment apart from the slight twitch and hair loss and the little green men who keep following me around....

 

[tree-peony]

oooooo you have the little green men as well LGC???? :roll: :wink:

 

[hanadr]

sid
I may be one of the longest term low carbers and rarely take any kind of supplement. I've nothing against supplements, but I eat a whole food diet and never remember to take anytthing else[ except the occasional Vit D.And Iwouldn't need that if the sun would only come out.] Many people are Vit D deficient this year. It's hard to get from food too.
Hana

 

[IanD]

I have seen a strong case for general mineral deficiency due to intensive agriculture. Only NPK are added as fertilizers, & the soil is depleted in minerals.

I take a multivit/min supplement. Blood tests have not indicated any deficiency. My wife is D deficient & takes prescribed tablets - but then she does not eat a low carb diet.

I did a cognitive test for Imperial College's SABRE study. Although I was suffering from serious tea deprivation, I passed the test. I've bumped up the SABRE thread if you want to read it.

The SABRE thread has been locked.

 

[jopar]

the mechanism for moving fat/protein to and from your own body tissues is different from absorbing and breaking down external nutrients but why is this 'minimum carb for the brain' thing such a big deal? Oh, and if the real issue is the waste products created by breaking down fats and proteins, why is this O.K. to fuel the muscles and other organs but not the brain?

N.B I've put 2 sentences from different parts of the LGC OP, so will read slightly out of context!

It's more to do with the brain's ability to access 'fuel' quickly and easily!

The brain doesn't have blood vessels directly inside of it, so it receives glucose nourishment from the Cerebrospinal fluid (CFS) but the glucose levels in the CFS lags behind the bloods glucose levels... Hence why you can still be standing with levels as low at 2mmol/l because there's a slightly higher amount of glucose in your CFS feeding the brain, and while it can take 30/40 minutes for full ability to concentrate after you've had an hypo as the CFS is still fuelling the brain to full capacity...

Muscles and other organs get their fuel directly from the blood..

30g's of carbs a day is the minimum to keep the basic functions of the brain going, your heart beating, and you are reasonably aware etc... And the rest of it of the glucose it requires can be sourced via a ketonic/VLC diet as long as the glucose levels in the CFS is maintained the brain will continue to do it's bit..

But there are some limitations though...

The Ketonic diet, works well when the intake of source food is very well balanced with energy output and it's up an running... Some of the side effects for a won't of a better word, for those starting out on this type of diet is a period when it's difficult to concentrate fully, a drop in energy levels etc as the body swaps it's primary fuel supply over the body has to work harder to supply enough for the CFS to keep the brain supplied...

Another limitation can be replenishment lags...

It takes longer to replenish fuel stock with a ketonic diet than it does with a carb diet, has T1/insulin users know if you hit hypo, a slab of meat is going to be totally useless in bailing you out, you've got to have a fast acting carb! So if you deplete your fuel supply with sudden increase or burst of energy, the recovery time is slower..

Probably why yes you hear of marathon runners following a VLC diet, but not heard of a Sprinter following a VLC diet!

 

[xyzzy]

As I clearly stated in the "Informed choices - downsides of LCHF?" thread I take Q10 because of the evidence that taking statins reduces the bodies production of Q10 nothing to do with being on a low carb diet.

Read here http://www.drbriffa.com/2009/03/02/...rterial-function-in-statin-treated-diabetics/ or if you don't like Dr Briffa try the Daily Fail which commented on the same issue http://www.dailymail.co.uk/health/article-432395/Statins-truth.html For some actual science research then try this one http://www.ncbi.nlm.nih.gov/pubmed/16872244 which includes the statement

Simvastatin and the combination of simvastatin and ezetimibe significantly decrease plasma CoQ10 levels

Likewise I take (or was taking) Vit D as I sit indoors in quite a light restricted area for most of the day when I'm working. I am getting my Vit D levels tested in the coming weeks after discussing this my GP. Again nothing to do with a low carb diet.

To state I take those supplements because of a low carb diet is erroneous and misleading.

 

[borofergie]

30g's of carbs a day is the minimum to keep the basic functions of the brain going, your heart beating, and you are reasonably aware etc... And the rest of it of the glucose it requires can be sourced via a ketonic/VLC diet as long as the glucose levels in the CFS is maintained the brain will continue to do it's bit..

No. Your brain requires 30g of glucose. This doesn't have to come from your diet - you can easily make more than this via gluconeogenesis.

But there are some limitations though...

The Ketonic diet, works well when the intake of source food is very well balanced with energy output and it's up an running... Some of the side effects for a won't of a better word, for those starting out on this type of diet is a period when it's difficult to concentrate fully, a drop in energy levels etc as the body swaps it's primary fuel supply over the body has to work harder to supply enough for the CFS to keep the brain supplied...

It takes 2 to 4 weeks to adjust to ketogenic diet, during which time some people report "flu like symptoms" and fatigue. In my experience, once you have passed this phase, energy levels, athletic perfomance and mental capability are increased.

It takes longer to replenish fuel stock with a ketonic diet than it does with a carb diet, has T1/insulin users know if you hit hypo, a slab of meat is going to be totally useless in bailing you out, you've got to have a fast acting carb! So if you deplete your fuel supply with sudden increase or burst of energy, the recovery time is slower..

It takes a longer time to replenish glycogen supplies but, unless you are an athlete, you'll be using so little that you don't need to replenish it. 30g of glucose is a teaspoon of sugar.

Probably why yes you hear of marathon runners following a VLC diet, but not heard of a Sprinter following a VLC diet!

High intensity anaerobic exercise is fuelled by glycogen.Low intensity exercise is fuelled principally by fat.

If you are a sprinter you need to eat carbs. If you are not a sprinter, then you probably do not need to eat carbohydrate. I run 5k a high-intensity (93% of my max heart rate) without eating any carbs.