I've recently started reading "The Art and Science of Low Carbohydrate Living" by Jeff Volek and Stephen Phinney. I quote:
"However this appears to be a flaw in human design because liver ketone production does not kick in until daily carbohydrate intake is consistently at or under 50 grams (200kcal) per day for a number of days. Thus there appears to be a functional gap in the body's fuel homeostasis when dietary carbohydrate intake is consistently somewhere between 600 and 200 kcal per day".
In the same book, the authors say that the brain consumes about 600 kcal per day. From this, I take it that in order to adequately support your brain, you need either:
1) a diet that restricts carbs to under 50 grams daily, so your liver can produce the ketones your brain needs.
2) a diet (that together with the process of glycogenesis) can provide about 600kcal/day (so about 140 - 150 grams of carbs).
Thus, anything in the middle (so between 50 and 150 grams of carbs per day) seems to fail in properly supplying the brain with the energy it needs.??
Is this correct? Am I missing something?
This is important to me, because I find 50g of total carbs per day to be highly restrictive - it does not allow me??to eat a lot of plant food and the variety is impacted as well. I find that maintaining my carb intake under 100g a day (or even 80g)??is much more attainable long term.
So what are your thoughts on this?
asked bybob89 (5)
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on March 09, 2015
at 04:35 PM
Generally, you don't count leafy greens in the carb calorie count.?? You'd only count things like starches or fruits.?? When I first went paleo, I "cheated" my 50g carbs/day with lindt chocolate truffles.?? This was before they started adding barley malt extract to these, so I don't suggest you do that now.?? Certainly it wasn't ideal as the carb was pure sucrose, but even so, it worked and I burned off a lot of fat.?? I don't know whether I was in ketosis or not, but I did have all the signs of it, other than bad breath.
I do have an issue with the language, we're "evolved" not "designed", so there may be many loopholes, or issues in what our bodies do.?? Some are hackable, others are not.
For example, you can hack ketone production by ingesting MCTs - ketones can feed most of the brain, and we do convert protein into glucose via cortisol signalling (gluconeogenesis).?? As long as you consume enough protein, there shouldn't be an issue.?? However, for some, the added stressor of excess cortisol is problematic.?? (I failed at this myself by doing both VLC and IF, even did alternate day fasts, and the result was fat gain, high stress levels, failure to get restful sleep.)
If you want to know for sure,??this thing (ketonix) is very useful.?? The one on sale now isn't the one I own, so I can't speak for it, the one I have plugs into a USB port, it must warm up, and a lot of time it's a pain in the rear end - takes more than 5 minutes for it to warm up.?? After this you blow into it for about 20-30s in one breath and it blinks different colors to let you know the ketone range.
The best way to test is with a blood ketone meter, but the strips are too expensive.?? Ketostix and the like aren't too useful as they measure what you're not absorbing.
You may find that for you, perhaps 100g of carbs a day is fine, or maybe even 50g a day is too much.?? It varies by the person.?? Obviously a 6'5" 250Lbs male body builder isn't going to get the same effect from 50g of carbs as a 5'0" 98lbs endurance athlete female.?? (If anything the endurance athlete will need more carbs.)
on March 10, 2015
at 06:49 PM
I never quite understood this low carb thing. Without carbs, basically all your fermentable fiber is gone. It is like giving up SCFA from food. The major sources of fermentable fiber are roots, tubers, grains, pulses, and fruits like apple or squash.