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Comment by snitch182 | Hacker News Reader

Does that mean you do good by your brain when you do a hard burn exercise once in a while ? After all those substances are a byproduct of burning fat instead of glucose by your liver. Or do i need a fat rich feast ?

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Your body starts producing ketons when you stop eating. Typically it starts 12 to 24 hrs.

It'll start faster if you don't eat carbs / sugar and instead use protein because the body start producing ketons when it runs out of glycogen stores. Sugar and carbs add glucose to your blood. The less of it you have, the faster the body will start producing ketons.

Exercise also helps because it uses glucose faster. Of course assuming you'll not just start eating carbs / sugar after exercise. That includes all drinks that include sugar.

But really you'll get most benefit of exercise just from a walk after meal.

Why after meal? Because that's when glucose spikes and a walk uses glucose faster.

Don’t you produce ketones any time you can’t get enough energy from carbohydrates?

Your body usually stores 1-2 days worth of “glucose” energy in the form of glycogen in muscle tissue and the liver

You have it backwards. Your liver can convert protein into glucose in a process called gluconeogenesis https://en.wikipedia.org/wiki/Gluconeogenesis

eat as much fat as you want, just leave out the carbs and sugar

Or just take a ketone supplement and eat normal food.

Has any research been done on what happens when the body is in a state of high glucose and ketones at the same time?

Not that I’m aware of but a number of professional cycling teams have been using them for a few years so there may be something in the works.

Ketoacidosis.

I don't think elite cycling teams would be taking these supps if it caused that, do you?

I frankly don’t care what you believe, but I do care about the ability of the general population to understand reasoning and logic. To that end, please understand that what you’re arguing is not a counter-example like you seem to think it is. It’s an argumentum ad populum - you’re saying this must be true because elite cycling teams are doing it. This is not a proof. It’s not even evidence, you’re not even citing something specific enough to call it that.

Again, believe what you want just make sure you understand that you’re not making a sound argument.

You should probably look into the supplements I’m referring to before launching into a diatribe.

You seem to think that would affect my statement. Pay attention to what I’m actually saying. I have no opinion on the supplement. It’s still invalid reasoning regardless of whether the supplement is effective.

The dose makes the poison.

Also, have you heard of Lance Armstrong? Do you think elite cycling teams worry more about health or performance?

It's a sliding scale from no harm to performance benefits to death. Clearly they are intelligent and educated and those teams expend effort to stay to the left of death...

You have a source for that? It’s my understanding that ketoacidosis is pretty hard to achieve unless you’re diabetic or some other serious medical condition. It is not the same as ketosis.

Ketoacidosis would be easy to achieve by just taking too many exogenous ketones too quickly. Ketones are acidic, the body doesn't like to have unbalanced blood pH.

It is rare without ketone supplementation, because unless you're fasting, eating a ketogenic diet, or are diabetic, the body doesn't usually have a high concentration of circulating endogenous ketones.

Diabetics can become so insulin resistant that their cells no longer uptake glucose, so they must fall back to burning ketones for energy, even while blood sugar is very elevated and food intake is normal. This is why DKA is so dangerous and (relatively) common.

Nothing about ketoacidosis is limited to diabetics - its just not common in non-diabetics, because how would you get such high concentrations of ketones? ...

@sgonz That state results in ketoacidosis, which is fatal.

"The dose makes the poison"

True.

But contrary to fats (or proteins or fibers), sugar is also addictive, doesn’t satiate your body, and ultimately generates hypoglycemia some hours later for you to eat more sugar.

So yes, the dose makes the poison but sugar is the only one poison your body accepts to absorb in immense quantities.

This. It is hard overeat if your diet consists of fish, nuts, seeds, and olive oil.

Nuts, seeds and olive oil are all extremely high in calories.

It is not intuitive, but a diet high in fat will make you less fat than a diet of sugar and carbs. The calories in nuts are not all absorbed.

Thus they are very filling if you eat a reasonable amount and not a can of them. I eat them at meal time and not as snacks, it’s easy to forget how many times you’ve grabbed a pinch of them if you “snack” on them throughout the day. Nuts are very nutritive as well, unlike pretty much any other snack heavy in sugar/fat

Good fats. Stay away from human manufactured fats like transfats like it’s your religion.

> Does that mean you do good by your brain when you do a hard burn exercise once in a while ?

There's a whole bunch of stuff happening in your body post strenuous exercise so it'd be hard to isolate ketones specifically from that.

But yes, exercise is very good for the brain.

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