X-Pert Course second update

dbr10 said:

130g of carbs we need to preserve brain function

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dbr10 said:

Not so much an update, actually, as going over much of the same material.

DN did ask if anyone was trying low carb. I was the only one. The others had higher Hba1c numbers, but thought they were doing okay, sadly.

The nurse was also confused about the difference between nutritional ketosis and keytones in the urine indicating DKA - where the actually problem is high BG in combination with dehydration.

And there was another mention of the 130g of carbs we need to preserve brain function.

I left with the impression that low carbers are making some progress, but still at a snail's pace.

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DavidGrahamJones said:

That might explain a lot of my brain fog. I'll dig deeper. I'm always suspicious of scientists quoting a finite limit, although I'm not going to argue with BG limits recommended.

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I’m not sure when this started being communicated in Diabetes training courses, but I am sure of the origins of the idea that 140g of carbs is the minimum required to be eaten every day. It stems from research done by Cahill et al in 1968 that suggests that for the brain to run exclusively on glucose, it requires between 110g and 140g of glucose per day. This book details the studies where this value was determined.

Okay – we have the origin of the 140g – but note that this is glucose and what the brain requires if running exclusively on glucose. It doesn’t say that we need to eat 140g of carbs.

Further research looking at the brain’s use of fuel sources identified that the brain uses lactate when undergoing strenuous exercise (http://www.fasebj.org/content/22/10/3443.full) and on page 277 of this document the following statement is made:

In individuals fully adapted to starvation [or low carbohydrate diets], ketoacid oxidation can account for approximately 80 percent of the brain’s energy requirements (Cahill et al., 1973). Thus, only 22 to 28 g/d of glucose are required to fuel the brain. This is similar to the total glucose oxidation rate integrated over 24 hours determined by isotope-dilution studies in these starving individuals (Carlson et al., 1994; Owen et al., 1998).

Or in other words, when not running on a glucose metabolism, the brain requires less than 30g of carbs and can be 80% fuelled from ketones.

The human body is perfectly capable of creating less than 30g of glucose a day through gluconeogenesis, so will destroy muscle if there is not enough protein or carbs free to feed the brain.

But the key thing is that you don’t need glucose to provide energy. You can get it other ways, but that’s the next myth…!
What this adds up to is that a human does not need 140g of carbs per day to feed the brain or to be healthy. If anything, it suggests that you don’t need more than 30g!

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