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Comment by itchyouch | Hacker News Reader

I think the problem with most sugars is that most people don't understand that the bulk of it is stored as glycogen in the muscular system.

Sugars really only have several places to go once they are ingested: Held in the fiber of undigested food, blood stream, liver and muscles.

We do really well with vegetables even though they are carbs since veggies are mostly fiber and very low carb. The high glycemic foods are okay provided that muscle glycogen is going-to-be/has-been depleted in the form of physical exertion.

Building muscle would also increases ones capacity for storing said glucose, but it's not easy or popular since the rate of muscle growth at best is about 1-2lbs/month under ideal conditions of physical exertion, nutrition and rest.

However, exercise and low-glycemic diets do explain the efficacy of reveesing t2 diabetes.

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CHO storage in muscles and mostly kidney only amounts to about 2000kcal worth of energy. So there is a very high turnover and already over a week it's averaged out to the point where it doesn't really matter if what you eat is carbs or fat.

So for healthy, non-diabetic people it really doesn't matter.

(With the obligatory addendum that going all "low-carbs" or "keto" is a very, very bad idea if you expect to do any exercise at all)

Why would keto be a bad idea? Genuine question. A friend of mine just run a 54k mountain track (2600m elevation) after 7 months keto. I have barely eaten carbs for 2 weeks now, and just cycled 120 km two days ago.

The short summary is that aerobic exercise performance in humans is limited by the maximal rate of oxygen uptake or VO2max. Oxidation of fatty acids requires more oxygen per unit of "energy" produced than glycolysis; they are simply less bang for buck (or oxygen). Hence chronically depleted (particularly muscle) glycogen stores are a great recipe for bad exercise performances as you force the body into deriving more energy from fats.

Now, in reality, energy during exercise is always derived from a mix of both fatty acids and glycogen. In general, as exercise intensity increases (you are getting closer to VO2max), a larger ratio of energy will be derived from glycogen. So for your friend, running 54k of mountains is only going to be done at rather low intensity (50-60% of VO2max), where ~60% of energy will be from fatty acids, saving glycogen and preventing hypoglycemia.

Hypoglycemia, incidentally, is also known as "bonking". It's rather unpleasant. On long, high intensity exercise sessions you can't usually replace all the glycogen you deplete through food intake. So if you start with lower glycogen stores through a low carb diet, what you are doing is priming your body for hypoglycemia.

These kind of scary warnings apply to almost no one, basically olympic atheletes in ketosis, and can be treated with a glass of orange juice. For the other 99% of us, ultimate performance is not the goal, and keto is a great way to stabilze blood sugar.

What scary warnings? This is basic exercise science. It applies regardless if your VO2max is 88 or 30, and indeed John Doe is more at risk of hypoglycemia as higher utilization of fatty acid oxidation at lower exercise intensity is one of the primary adaptations gained through training.

Do you have a scientific source for these claims? Dr. Peter Attia's personal research seems to claim otherwise.

http://eatingacademy.com/how-a-low-carb-diet-affected-my-ath...

Most Olympians are going to be on a high carb diet. What records has Attia set in sports?

Very scientific.

Very crass.

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