A similar misconception is "I need glucose therefore I should eat sugar" .
The most stable way to supply blood glucose is by eating fat. If blood glucose is high and circulation is low, then exercise maybe in order, more than additional eating.
The most stable way to supply blood glucose is by eating fat. If blood glucose is high and circulation is low, then exercise maybe in order, more than additional eating.
Try doing a 100km bike ride on an up/down road circuit, with fat as the main fuel.
EDIT: lol, downvotes. This is not about your metabolism while you're sitting on a chair at work, typing on a keyboard. This is about extreme endurance. I suggest you actually go ahead and try it, before thinking you've formed any sort of informed opinion on the subject.
Here is a link to a summary, I couldn't find the actual research articles I was thinking of though.
http://www.pponline.co.uk/encyc/sports-nutrition-should-athl...
It is fair to point out (which the article does as well) that the athletes were running at 75% of V02 max, which is lower than when racing in cycling. I ride a lot, and anecdotally I had a cycling teammate that changed his diet to consist of primarily fats for 6 weeks. The first few weeks his body was adjusting and his endurance and power dropped dramatically as you would expect. After 4 weeks, though, he had come back and had a really strong season.
The way I understand it is that as intensity increases it becomes more difficult for the body to convert fat for a large source of fuel, and glycogen becomes the largest contributor to energy. I know the feeling of a "bonk", when glycogen depletes, is a really strange one and all fuel is coming from fat at that point and intensity has to drop by quite a bit in order to continue.
Our bodies are pretty amazing
There's only one thing that gets you out of it quickly - and that's a shovel full of carbs.
Your body definitely needs time to adapt to a fat based diet, but it can satisfy all your energy needs.
I've also done centuries with sugary 'energy' foods. I frequently found myself having to pull over or dangerously balance in order to keep my blood sugar high by dosing myself every 45 minutes. Your stomach churns, your teeth feel awful, being constantly in service to your legs. Burning the fat is a much more comfortable proposition.
I am not an extreme endurance athlete, but I have heard multiple anecdotes of extreme endurance athletes eating cheese pizza slices during their 100-200 mile runs. It's actually a fairly common theme ...
ALSO: Do NOT meta-discuss your own downvotes. Don't interrupt the discussion to talk about the scoring.
Well cheese is a good mix of protein and fat, and the base is full of carbs
Nah, let's do exactly that. I see too many controversial posts which are otherwise good quality and contribute to the discussion, get downvoted because people don't agree with them. I don't care what pg says - downvoting merely for disagreement is fucking stupid, and it's lazy.
If I wanted a hivemind I'd go to proggit. When this community votes on posts based on quality, and not on who wrote it and whether they agree, then we can call people out for complaining about downvotes. Until then (i.e. until never, probably), if you feel you're being unfairly downvoted, bitch about it as loudly as you want - you will get at least one upvote from me when you do.
Also, doing a 100km bike ride with fat as the main fuel would actually be exceptionally easy if you used the proper technique, because the entire purpose of the gearing system on racing bikes is to ensure your exertion remains the same. It would just require training with this goal in mind, like Timothy Oslon who's a successful ultramarathon runner.
> I suggest you actually go ahead and try it, before thinking you've formed any sort of informed opinion on the subject.
I would suggest you do the same, because you don't seem too well informed either.
The metabolic pathways which do produce glucose are:
1) Eat starches.
2) Eat protein.
Starches are converted directly to glucose. Protein can be converted to glucose by a process called gluconeogensis. This is what happens under either a starvation situation (in which case the protein is supplied from body tissues -- skeletal muscle and eventually organ tissue), or under a ketogenic diet, in which dietary protein could be utilized.
While dietary glucose is apparently not necessary, it's also not a bad thing, provided you're not getting excessive quantities or low-fiber sources which trigger an excessive insulin response.
That said: the typical Western diet provides more than ample glucose and starches, often in an overly refined form. That can trigger lipogenesis, in which excessive glucose is converted to lipids and stored as fat.
These are evolutionary adaptions that let us extract energy efficiently from our environment, maybe yesterday's sensationalist news about our alcohol dehydrogenase efficiency is proof that we should use alcohol for all energy needs.
Now, what i really wonder is; if we see diabetes from abusing the carbohydrate pathways, then what disease comes from abusing the ketone/gluconeogensis pathways ?
The body can't easily/quickly convert fat into glucose.
"""acetic acid (in the form of acetyl-CoA) is used to partially produce glucose; acetyl groups can only form part of the glucose molecules (not the 5th carbon atom) and require extra substrates (such as pyruvate) in order to form the rest of the glucose molecule. But a roundabout pathway does lead from acetyl-coA to pyruvate, via acetoacetate, acetone, acetol (hydroxyacetone) and then either propylene glycol or methylglyoxal."""
Minimum daily glucose requirements are on the order of 100g, possibly higher. If this pathway cannot sustain that delivery rate, it's not significant.
Just answered your initial comment that was "The body cannot convert fat into glucose at all".
So it's a little moving-the-goalposts disingenous to brush this off as "it's not significant for our daily glucose requirements", when your initial claim was much stronger and this refutes it.
As I'd indicated in another response, I wasn't aware of pathways other than straight carbs or synthesis from protein (and knew of but forgot about the glycolysis/pyruvate pathway). I appreciate the new information.
https://news.ycombinator.com/item?id=8698478
My question simply as read: do you know of rates of production of this pathway? If it cannot meet ~100g/day or a significant fraction of that, then it's not really materially significant, though it is of interest. If it can, well, then, that changes things.
Answering the question or stating "I don't know" would be acceptable.
So there's one anecdote for you.
Turns out my own feelings about sharpness has absolutely nothing to do with congnitive ability. Who would have thought?
Now I am eating about 200g/day of carbs (mainly from rice and veggies) and I feel much better. My weight remains the same.
This is a good intro to the potential problems of chronic ketosis [1].
[1] http://freetheanimal.com/2014/02/ketogenic-diets-news.html
note: Saccharose, which is Glucose + Fructose can help with that as well
Researchers who lived with the Inuit (Vilhjalmur Stefansson etc.) did not have any problems following the Inuit diet.
[1] http://freetheanimal.com/2014/03/disrupting-carbs-prebiotics...
I would like to see a citation for this. My metabolics text book says that generally fat cannot be made into glucose. Only the glycerol bit can, and that is only a small fraction of the calories in fats.
There may be just a germ of truth in what you say, in that for some people eating large amounts of carbohydrate leads to drastic fluctuations in serum glucose.
When you are eating excessive sugars and carbs like most people today, your body doesn't burn fat. You only use sugars for energy. That's why you have your energy levels constantly up and down.
I have been on ketagonic diet last 3 months. I eat no sugars and less than 50gr carbs. My energy levels are always stable now, lost 20lb. I don't need glucose for energy.
I see it as winter mode vs summer mode:
- If it's is summer there are sugars and carbs. So, your body keep storing as much fat as possible and uses carbs for energy and pushes you to eat as much as you can. Making you feel hungry all the time so you eat more and store more fat.
- if it is winter, there are nothing much to eat, so your body uses fat as energy.
The problem with modern world is that there are just so much food and carbs around us that we are always in summer mode.
That's not a misconception, it is reality. It is amazing how many people on HN really hate science. Diabetics are told to eat juice or candy when their blood sugar is low for a reason.
>The most stable way to supply blood glucose is by eating fat
That is also too slow to be of any use.
Counterpoint: medical science is insanely difficult and expensive, due to individual variations in genetics and lifestyle, and the huge number of variables that it is effectively impossible to completely control for. This leads to research that is tainted by the incentives of those agents that afford the expense, and results that tend to be correlation more often than causation.
That's not to say that we should ignore the science we do have; rather, we shouldn't fall into the trap of assuming we can model biology as precisely as astrophysics. Sometimes the illusion of knowledge is more dangerous than ignorance.
Inflammatory language like this (as well as in https://news.ycombinator.com/item?id=8696794, https://news.ycombinator.com/item?id=8696817, and other comments you've posted) adds to the problem. Assuming you're 100% correct on facts, railing against perceived idiots merely impedes the communication of the facts. It discredits your arguments, and it poisons the discourse. We all need to edit this kind of thing out of the comments we post to HN.
If I do not have glucose on my person then I'm advised to drink anything that is "liquid sugar" - juice, pop, milk (lactose) because it raises the blood sugar quickly.
But you need to consider this is because our bodies are DEFECTIVE. When my blood sugar goes to 30 (been there, done that) I need a blood sugar spike RIGHT NOW. And by right now I mean before I pass out, slip into a coma, and DIE.
So when I am presented with a number so low that I am about to be seriously fucked, and I don't have my tablets with me, I'll eat every fucking carbohydrate in sight because a high blood sugar might kill me in 20+ years, but a low can kill me right now.
Outside of potentially LIFE THREATENING low blood sugar levels diabetics are encouraged to try to stay away from foods that fall into the high glycemic index categroy. This is because they raise blood sugar fast, and then they crash back down just as fast. This is what most of us diabetics refer to as the "Roller Coaster"; and we do not like coasters.
http://www.diabetes.org/food-and-fitness/food/what-can-i-eat...
The really great thing about healthy non-diabetics is your body is really good at self regulation, so your "lows" will likely never go below 70 (e.g. Not dangerous), and even after gorging yourself on an entire pizza and chasing it with a 2 liter bottle of Code Red Mountain Dew your body will still keep your blood sugar maxed at an also healthy 100.
So please don't talk like you understand diabetic science or that it in anyway relates to normal, healthy functioning adults. It is the equivalent of trying to say that someone without cancer should get chemo, because it helps people with cancer. It's not like you are going to pass out and die or possibly have your blood turn into acid and poison you to death (yes this is a real risk for a Type 1 diabetic http://www.diabetes.org/living-with-diabetes/complications/k... http://en.wikipedia.org/wiki/Ketoacidosis)
Me too.
>So please don't talk like you understand diabetic science
Please don't be a condescending prat when what I said is 100% accurate.
Diabetics are allowed to eat sugar, and research indicates that the source of carbs really doesn't matter: http://www.diabetes.org/food-and-fitness/food/what-can-i-eat...
Commonly used and recommended sources of sugar to treat hypoglycemia in diabetics include fruit, soda, juice, candy, sugar, honey and skim milk: http://www.diabetes.org/living-with-diabetes/treatment-and-c...
And the bottom line is the dietary dos and do nots for diabetics just don't apply to healthy people. They are on a different playing field.
Nobody said they did. So, why the angry long rant directed at me exactly?
On the first point,
>>A similar misconception is "I need glucose therefore I should eat sugar" .
>That's not a misconception, it is reality. It is amazing how many people on HN really hate science. Diabetics are told to eat juice or candy when their blood sugar is low for a reason.
Yes, sugar is absolutely necessary for energy. Fat as fuel is pseudo science BS. On the other hand most people consume way more sugar than is necessary and the sugars we take when our blood sugars are low are not the best sources of sugar for a general diet and long term fuel source.
On the second point,
>>The most stable way to supply blood glucose is by eating fat
>That is also too slow to be of any use."
Fats, fiber, and protein are pretty great for fueling stabilized blood sugar since they lower the GI of carbohydrates. While this is not good for low blood sugar, it is great for maintaining stable lower fluctuating blood sugars. So the general advice for a healthy person to eat more fats and less carbs is overall some pretty good as advice as there is very strong evidence that it lowers risk of Type 2 diabetes. As for Type 1, obviously you're just fucked no matter what you do.
Anyway, was not trying to be a "prat", and the TC is wrong on the whole point of
>A similar misconception is "I need glucose therefore I should eat sugar".
Your post came off to me though as the opposite extreme; while not explicitly stated, it seemed to imply that the people saying they should eat/drink high GI food/drinks to raise blood sugars, but really they should probably be eating more lower GI foods.