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Low carb diet that provides enough energy to the brain

Commented on March 10, 2015
Created March 09, 2015 at 3:50 PM

Hi all,

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?

Medium avatar

(128)

on March 10, 2015
at 10:05 AM

Yeah i've also read Sisson saying most PBers are around 70-90g net carbs with exercise, when low carb i feel best around that mark myself, if i go to under 50 net carbs then i need to eat a decent amount of protein to feel like i'm not withering away as i'm already quite skinny, and that's just too expensive and not sustainable in my experience

Ffd1fd1e315e4bbff2c87872d53f93fc

(5)

on March 09, 2015
at 08:22 PM

@PaleoRob which confuses me given that many high profile paleo people recommend the 50-150g carb intake zone. See for example marksdailyapple . com / how-to-succeed-with-the-primal-blueprint (sorry for spaces I am not allowed to post links) where 50-150 seems to be the recommended carb intake.

Medium avatar

(128)

on March 09, 2015
at 07:19 PM

I heard volek in an interview saying hovering between 50 and 150g net carbs in the long term may not be desirable for the reasons you mentioned

As long as it isn't starch or fruit its easy to eat loads of plant food and stay under 50g if you really want to

 

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2 Answers

1
96440612cf0fcf366bf5ad8f776fca84

(19483)

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.)

Be157308a0438e382b88d9db4c12ab30

on March 09, 2015
at 08:55 PM

@bob89

" I'm guessing the total carb intake would count the carbs in leafy green vegetables as it includes fibre."

No you don't count the fiber. No low carb diet counts the fiber. You can eat unlimited fiber on a low carb diet. Only the NET CARBS (total - fiber = net) count. So you can eat as much spinach, kale, collards, etc as you like since these have almost no net carbs. You could eat a bucket of vegetables a day and still be under the 50g limit so long as you eat leafy vegetables.

Ffd1fd1e315e4bbff2c87872d53f93fc

(5)

on March 09, 2015
at 08:28 PM

Thanks for your answer. The thing is in their book, they recommended 25g net carb intake or 50g total carb intake. I'm guessing the total carb intake would count the carbs in leafy green vegetables as it includes fibre.

I actually thought about MCTs and that's one reason I increased my intake of coconut oil, so that's a good point.

I will continue to experiment and see what works, but I'm a bit worried about potential long term effects on brain health if energy supply is not adequate.

-1
56c28e3654d4dd8a8abdb2c1f525202e

(1822)

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.

Be157308a0438e382b88d9db4c12ab30

on March 10, 2015
at 09:37 PM

Wrong. Fiber can be consumed in unlimited quantities in low carb diets. Avocados provide a ton of fermentable fiber and are definitely low-carb. Same thing with coconut meat and pulp, plenty of fiber there and very low in carbs. Not to mention dozens of other low carb fruits and vegetables like tomatoes, cucumbers, zuchini, turnips, radishes, cabbage & sauerkraut, broccoli, cauliflower, onions, etc. Plenty of soluble fiber to be had there. 

There's millions of things you don't understand, but that doesn't mean they don't work.

56c28e3654d4dd8a8abdb2c1f525202e

(1822)

on March 10, 2015
at 10:07 PM

I don't think cucumbers, zucchini or cabbage have the same amounts of fermentable as the other ones. Roots are roots, which I listed. Do you have numbers somewhere?

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