Ketogenic diet - fad or phenom?

[LMT]

15-20 million years of human evolution has taught us that glucose is the primary source of fuel for the body and brain. When someone falls off the wagon by eating carb then they are only doing what is natural. No need to fret.

[The French Tandem]

I'm usually very skeptical about any diet that severely restricts one sort of food or another, but being of a curious nature, we decided to give it a try. Well, it was a very modest experiment. On sunday morning, my better half and I had eggs and bacon for breakfast, and nothing else, no bread, no jam, only a cup of coffee for drinking. Then we went out for a 80 km tandem ride. Considering our poor level of fitness at the moment, 80km is quite a long ride for us.  It was our fastest 80km for as long as I can remember, we didn't eat anything during the ride, although my pockets were full of energy bars, just in case, and we were even not hungry at the end. Today, I'm surprised to feel no pain in my legs as I usually feel the day after a fast ride.

I wasn't expecting a single breakfast before a ride to make such a huge difference. I'm not sure whether cutting the carbs is so magically efficient, or all I see is the result of some powerful placebo effect! Any thought? Does the carbs restriction have any known effect on post-ride recovery?

[ElyDave]

15-20 million years of human evolution has taught us that glucose is the primary source of fuel for the body and brain. When someone falls off the wagon by eating carb then they are only doing what is natural. No need to fret.

Er, no it isn't

Muscles can work very well on lipolysis, and the brain can utilise ketones very effectively

[chrisbainbridge]

Actually your body needs fatty acids (fat) and needs essential amino acids (protein) but can get all its glucose made in the liver.  There is no such thing as an essential carbohydrate.

[Manotea]

As a proof of principle, I've fallen from, 'I dont think I'll bother eating on an audax ever again' whilst in the Keto-zone, to seriously bonking out last W/E after ¬70km. Carbs? Just say no...

[zigzag]

for reference, i had four bananas at roughly 70, 110, 150, 180km of 204km audax and nothing else apart from 800ml of water. average speed 29kph, diet type - balanced

[LMT]

15-20 million years of human evolution has taught us that glucose is the primary source of fuel for the body and brain. When someone falls off the wagon by eating carb then they are only doing what is natural. No need to fret.

Er, no it isn't

Muscles can work very well on lipolysis, and the brain can utilise ketones very effectively

Er yes it is. Me thinks you have misinterpreted my post, nay bother I'll bold the bit that you misread.

[LMT]

for reference, i had four bananas at roughly 70, 110, 150, 180km of 204km audax and nothing else apart from 800ml of water. average speed 29kph, diet type - balanced

On the face of it and taking into account the average speed and power needed for said speed. I'd say a sound aerobic system, with plant based carbs to top up the energy levels that you would have burned pedalling up some hills or just 'giving it some' on the flats.

That's a thumbs up from me.

Someone on the Keto would have crashed and burned if they tried to keep up with you on a sustained climb.

[Chris S]

15-20 million years of human evolution has taught us that glucose is the primary source of fuel for the body and brain. When someone falls off the wagon by eating carb then they are only doing what is natural. No need to fret.

Er, no it isn't

Muscles can work very well on lipolysis, and the brain can utilise ketones very effectively

Er yes it is. Me thinks you have misinterpreted my post, nay bother I'll bold the bit that you misread.

I suppose it depends what you mean by "primary". If you mean - it's what the body will use first given a choice, then yes it is - a carbohydrate rich meal will trigger an insulin response in order to moderate blood sugar, and any excess will be burned (if you're active) or converted to fat and stored (if you're binge-watching Netflix).

But once you are no longer in a recently fed state, fat is the primary "background" source of fuel for aerobic activity. The brain can mostly function on either glucose or ketone bodies; only a few tissue types have an absolute requirement for glucose as energy - including: red blood cells, some cells in the brain, oh - and cancer cells it would seem (Ref: Warburg). Once you get into a ketogenic state, your liver will create any glucose the body needs (which is really not very much), and the rest of your energy needs are met by fat and ketones.

Someone on the Keto would have crashed and burned if they tried to keep up with you on a sustained climb.

Hehe - the very idea of keeping up with Zigzag on any terrain is fantasy to me! 

[LMT]

15-20 million years of human evolution has taught us that glucose is the primary source of fuel for the body and brain. When someone falls off the wagon by eating carb then they are only doing what is natural. No need to fret.

Er, no it isn't

Muscles can work very well on lipolysis, and the brain can utilise ketones very effectively

Er yes it is. Me thinks you have misinterpreted my post, nay bother I'll bold the bit that you misread.

I suppose it depends what you mean by "primary". If you mean - it's what the body will use first given a choice, then yes it is - a carbohydrate rich meal will trigger an insulin response in order to moderate blood sugar, and any excess will be burned (if you're active) or converted to fat and stored (if you're binge-watching Netflix).

But once you are no longer in a recently fed state, fat is the primary "background" source of fuel for aerobic activity. The brain can mostly function on either glucose or ketone bodies; only a few tissue types have an absolute requirement for glucose as energy - including: red blood cells, some cells in the brain, oh - and cancer cells it would seem (Ref: Warburg). Once you get into a ketogenic state, your liver will create any glucose the body needs (which is really not very much), and the rest of your energy needs are met by fat and ketones.

Someone on the Keto would have crashed and burned if they tried to keep up with you on a sustained climb.

Hehe - the very idea of keeping up with Zigzag on any terrain is fantasy to me! 

De novo lipogenesis, look it up before you state something like the above.

If my glycogen stores were empty and I was on a plant based diet I'd need to eat about 120 bananas before any carbs were stored as fat, and even then this is on a 30/100 ratio in terms of fat/carbs.

The only thing that makes you fat is......fat - who'd have thunk it. . Those on a keto diet? Perhaps, but the brain fog that occurs through eating a diet rich in animal products and saturated fat prevents this sort of critical thinking and connection from happening. Ho hum.

EDIT: And as for the whole cancer thing, cancer cells thrive in an acidic environment. Answers on a postcard please for what diet will make your blood the most acidic?

Clue: It involves eating a dead animal, eating the menstrual cycle of an animal, or drinking the product of an animal.

[simonp]

Before my fat burning test in April I ate a high carb, moderate fat, moderate protein breakfast. Yet during aerobic exercise, I got most of my calories from fat. The reason for this isn't my diet, it's a lot of aerobic base training. The mitochondria in the muscles respond to training, and I doubt that sitting on your arse eating avocados and coconut oil will have anything like the same effect as drinking a black coffee and turning the pedals for a couple of hours.

[LMT]

Before my fat burning test in April I ate a high carb, moderate fat, moderate protein breakfast. Yet during aerobic exercise, I got most of my calories from fat. The reason for this isn't my diet, it's a lot of aerobic base training. The mitochondria in the muscles respond to training, and I doubt that sitting on your arse eating avocados and coconut oil will have anything like the same effect as drinking a black coffee and turning the pedals for a couple of hours.

 

Some common sense finally regarding diet and aerobic fitness. The keto/primal brigade will bang on endlessly about how this diet adds to endurance. But it's about training, and riding consistently at endurance power, something which is independent of your diet.

Although a high carb diet and hard training will of course raise your FTP and as such the Z1 & Z2 levels.

[Chris S]

If you want to be trained, you need to train - pfft, no one is arguing that.

[LMT]

If you want to be trained, you need to train - pfft, no one is arguing that.

But on low carb you cannot train beyond a certain threshold.

[Chris S]

If you want to be trained, you need to train - pfft, no one is arguing that.

But on low carb you cannot train beyond a certain threshold.

Tell that to this guy: http://www.samiinkinen.com/post/86875777832/becoming-a-bonk-proof-triathlete-fat-chance

[Cudzoziemiec]

Surely the training in Simon's case is that aerobic training has enabled him to burn more fat without adopting a carb-free diet. Body training not diet training.

[L CC]

If you want to be trained, you need to train - pfft, no one is arguing that.

But on low carb you cannot train beyond a certain threshold.

Bollocks.

[LMT]

If you want to be trained, you need to train - pfft, no one is arguing that.

But on low carb you cannot train beyond a certain threshold.

Bollocks.

I'll await your 20 mins Z4 effort then....

[pcolbeck]

EDIT: And as for the whole cancer thing, cancer cells thrive in an acidic environment. Answers on a postcard please for what diet will make your blood the most acidic?

Clue: It involves eating a dead animal, eating the menstrual cycle of an animal, or drinking the product of an animal.

Pseudo science nonsense. Your blood is Ph 7.4 (slightly alkaline) or there about it doesn't change and it's never acidic. If it changed much you would die. The body buffers the bloods Ph very effectively. If you blood pH starts changing you are seriously ill. How would you know if your diet was affecting your blood pH anyway (iit isn't but lets let that go) ? Do you take blood samples every day and test them ?

[hellymedic]

pcolbeck is spot on about blood pH.

The blood pH is adjusted by breathing and the kidneys.

pH of 7.3 is ill and <7.1 is often DETH.

[pcolbeck]

We are not designed to eat meat/dairy products, compare the bio-chemistry of those that are born carnivores with human beings. Their system is acidic and they can metabolise dietary cholesterol, we cannot.

Where do you get this stuff from. All mammals have roughly similar blood pH. The cat which is about as carnivorous a creature as you can get has a blood pH of 7.3-7.4 very close to ours and very definitely slightly alkaline not acidic.

[LMT]

If you want to be trained, you need to train - pfft, no one is arguing that.

But on low carb you cannot train beyond a certain threshold.

Tell that to this guy: http://www.samiinkinen.com/post/86875777832/becoming-a-bonk-proof-triathlete-fat-chance

I'd need to know his FTP before commenting.

[Si S]

We are not designed to eat meat/dairy products, compare the bio-chemistry of those that are born carnivores with human beings. Their system is acidic and they can metabolise dietary cholesterol, we cannot.

Where do you get this stuff from.

Maybe from one these

(click to show/hide)

[L CC]

If you want to be trained, you need to train - pfft, no one is arguing that.

But on low carb you cannot train beyond a certain threshold.

Bollocks.

I'll await your 20 mins Z4 effort then....

*sigh*
They're right there in my training log from last autumn when I was righteously keto, rigorously training, losing weight and generally kicking butt.

[simonp]

The results of the second test in that page are fairly similar to mine. Peak fat burning shown as 70% there and in my case peak was at 68% at roughly the same wattage.

My test wasn't performed in a fasted state, unlike those; I'd had a high carb breakfast and no caffeine (caffeine increases fat burning). If you note his argument, he's extrapolating his fasted fat burning performance to predict his non fasted performance. That's a bit flawed and one of the reasons I was told NOT to fast before my test.