New Trial: LCHF vs "Medium Carb Low Fat". Who Wins?

[borofergie]

Oh ok, cool.

What happens then if you train your brain to run mostly on ketones instead of mostly on carbs?

Then the brains requirement for glucose reduces to about 25g a day - all of which can be produced by gluconeogenesis from protein and fat, with the rest of it's energy coming from ketones. Ketosis is basically a glucose sparing strategy.

 

[Spiker]

Then the brains requirement for glucose reduces to about 25g a day - all of which can be produced by gluconeogenesis from protein and fat, with the rest of it's energy coming from ketones. Ketosis is basically a glucose sparing strategy.

So a bare minimum of 25gch, but as you say that could be produced by gluconeogenesis, from protein
PS Can't produce glucose from fat. See me after class. ;-)

 

[borofergie]

I read that in the low carbo paleo diet, if one was to follow it like our ancestor ewe would be eating very lean meats and insects / grubs etc but more important over 100g of fiber a day.

I don't think that the "lean meat" thing is true. For sure that's what Cordain wrote in his original paper, but most subsequent research suggests that hunter-gatherers would have eaten the whole animal (brains, and all) and got a high proportion of the calories from fat.

Why would you go to the trouble of hunting down an animal and neglecting the most energy rich part of the meat?

 

[borofergie]

So a bare minimum of 25gch, but as you say that could be produced by gluconeogenesis, from protein
PS Can't produce glucose from fat. See me after class. ;-)

I'm afraid that you can. They are called triglycerides, 3 fatty acids bound to a glycerol backbone. Once you've burned the fatty acids the glycerol get converted into glucose. About 10% of fat energy is turned into glucose.

Again. This is off the top of my head. Let me find a reference.

 

[Spiker]

Ketosis is basically a glucose sparing strategy.

Ha! i would say glucolysis is a ketone sparing strategy, since dietary fats - and hence ketones - have been much more available to us than dietary carbohydrates, over evolutionary time.

 

[runner2009]

I don't think that the "lean meat" thing is true. For sure that's what Cordain wrote in his original paper, but most subsequent research suggests that hunter-gatherers would have eaten the whole animal (brains, and all) and got a high proportion of the calories from fat.

Why would you go to the trouble of hunting down an animal and neglecting the most energy rich part of the meat?

Oh I agree with you 100% - they would eat everything just like the Plains Indians did with the Buffalo - I was inarticulate referring to our current beef with 9 1/2 grams of saturated fat per pound.


Sent from Runner2009 Burt

 

[Spiker]

I don't think that the "lean meat" thing is true. For sure that's what Cordain wrote in his original paper, but most subsequent research suggests that hunter-gatherers would have eaten the whole animal (brains, and all) and got a high proportion of the calories from fat.

Why would you go to the trouble of hunting down an animal and neglecting the most energy rich part of the meat?

I don't think the suggestion was that our ancestors wouldn't have eaten the whole animal, just that game animals were (and are) much leaner than farmed animals.

 

[Spiker]

I'm afraid that you can. They are called triglycerides, 3 fatty acids bound to a glycerol backbone. Once you've burned the fatty acids the glycerol get converted into glucose. About 10% of fat energy is turned into glucose.

Again. This is off the top of my head. Let me find a reference.

Hmm. I thought I had read that the gylcerol skeletons were reused rather than being broken down into glucose. But maybe in a ketogenic state I guess.

Edit: yep, checking, you can only metabolise the glycerol if you can tolerate reducing total triglycerides, which you would not want to do if you were running a primarily lipid based metabolism. If you burned glycerol, you would need new glucose inputs to create new glycerol in order to transport the same amount of fatty acids out of adipose cells. So while you can burn glycerol in isolation, as a steady state thing you can't burn net amounts of glycerol as a net glucose source.

 

[borofergie]

I don't think the suggestion was that our ancestors wouldn't have eaten the whole animal, just that game animals were (and are) much leaner than farmed animals.

Yes they are leaner if you only eat the muscle meat, if you eat all the organ meat too there is lots of fat. We don't tend to eat the organ anymore, so we don't get most of the best fatty bits.

 

[runner2009]

Yes they are leaner if you only eat the muscle meat, if you eat all the organ meat too there is lots of fat. We don't tend to eat the organ anymore, so we don't get most of the best fatty bits.

Yes, a variety of fats both short and medium chain saturated fats along MUFs - but I bet you it was not an every day occur acne or they went periods of feast or no fats


Sent from Runner2009 Burt

 

[borofergie]

Yes, a variety of fats both short and medium chain saturated fats along MUFs - but I bet you it was not an every day occur acne or they went periods of feast or no fats

I'm sure that they were perpetually on the edge of starvation.

Apparently the Inuits used to save the fatty bits of meat for their kids, and give the lean muscle meats to the dogs...

That's like me walking around Waitrose, I only choose the fattiest cuts of meat. Ribeye and brisket for me every time.

 

[borofergie]

Edit: yep, checking, you can only metabolise the glycerol if you can tolerate reducing total triglycerides, which you would not want to do if you were running a primarily lipid based metabolism. If you burned glycerol, you would need new glucose inputs to create new glycerol in order to transport the same amount of fatty acids out of adipose cells. So while you can burn glycerol in isolation, as a steady state thing you can't burn net amounts of glycerol as a net glucose source.

So I guess you are saying here: "yes Stephen, you can glycerol is a precursor for GNG, so you can create glucose from fat". Do I still got to see you after class?

 

[borofergie]

This is the Ketogenic Ratio:

Basically it is saying that (of ingested calories):
90% of fat calories and 46% of protein calories are ketogenic.
10% of fat calories and 58% of protein calories are anti-ketogenic

The 10% of fat is the glycerol molecule, the other 90% are fatty acids.
http://www.lucastafur.com/2011/05/total-ketogenic-ratio-tkr_21.html

 

[Spiker]

Any idea why the two protein terms add up to 1.04?

The lower protein term, 0.58, I recognise as the GNG conversion factor (of protein to glucose). Assuming all ingested protein went into GNG, which would never happen.

So what values of this KR ratio qualify as ketogenic, or not ketogenic? In other words how do you make use of the ratio?

Reading the linked article, it all looks a bit sketchy to me.

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[borofergie]

Any idea why the two protein terms add up to 1.04?

The lower protein term, 0.58, I recognise as the GNG conversion factor (of protein to glucose). Assuming all ingested protein went into GNG, which would never happen.

So what values of this KR ratio qualify as ketogenic, or not ketogenic? In other words how do you make use of the ratio?

From Lyle MacDonald:

For the treatment of epilepsy, the ratio of K to AK must be at least 1.5 for a meal to be considered ketogenic (1). Typically, this results in a diet containing 4 grams of fat for each gram of protein and carbohydrate, called a 4:1 diet. More details on the development of ketogenic diets for epilepsy can be found in the references, as they are beyond the scope of this book.

But he also says that it only works for an isocaloric diet - when your intake matches your energy output. If you eat less than you burn, you need to account for the extra body fat that you burn.

 

[Spiker]

From Lyle MacDonald:


But he also says that it only works for an isocaloric diet - when your intake matches your energy output. If you eat less than you burn, you need to account for the extra body fat that you burn.

That makes sense.

I'm still not sold on this glycerin burning thing. Particularly on a hypocaloric diet, you need that glycerin group to pull the next trigylceride out of adipose tissue, as a transporter. If you burn your transporter, you need to come up with another glucose molecule to build another glycerol transporter to get the fatty acids out of the adipose cell to burn. So in a steady state hypocalorific diet, you don't burn any net carbs for fuel. If you try to send the glycerol into GNG to provide glucose for the brain, you need to rob glucose from somewhere else in order to continue to supply triglycerides for lipolysis.

Maybe it does work as you describe though if the lipolysis is from free fatty acids which maybe includes dietary fatty acids, eg in an isocaloric or hypercaloric diet.

 

[phoenix]

I am wondering about the term(s) low carbohydrate and medium carbohydrate diet. I think there is one more component to track and that is the amount of fiber. I am not talking about the net carbohydrate calculation, but correlating the total carbs with total fiber.

In experimenting with my food intake if I chart that I want to eat >50g of fiber a day my carbohydrate intake is dramatically different than say even <25g. My nutritional values also go through the roof - not taking any fiber supplements.

I read that in the low carbo paleo diet, if one was to follow it like our ancestor ewe would be eating very lean meats and insects / grubs etc but more important over 100g of fiber a day.

Just a thought




Sent from Runner2009 Burt

The fibre element is I think very important. Forty years ago a low carb diet was the norm for diabetes
.It was the hypothesis that fibre intake was a major element in preventing/ ameoliorating diabetes that led to many studies pitting low carb (the 'normal' diet ) against higher carb. These diets were high carb but included between 50 and 90g fibre per day. It was these trials that led to present guidelines. ( these diets did not contain large amounts of refined starches, certainly not some of those foods often advised)
I've linked before to Jim Mann's recent Easd lecture where he discusses this. I also found this recently. It's an old paper , I can't find a date (probably 1980s, definitely not politically correct ! ). In it Prof Mann describes the background against why people started to investigate high carb/fibre diets and some of the results. (impossible to follow up references as the papers mostly aren't online ). http://apjcn.nhri.org.tw/server/markwpapers/mark_books/Downloads/RECENT ADVANCES IN CLINICAL NUTRITION/Diabetes mellitus.pdf

 

[borofergie]

I'm still not sold on this glycerin burning thing. Particularly on a hypocaloric diet, you need that glycerin group to pull the next trigylceride out of adipose tissue, as a transporter. If you burn your transporter, you need to come up with another glucose molecule to build another glycerol transporter to get the fatty acids out of the adipose cell to burn. So in a steady state hypocalorific diet, you don't burn any net carbs for fuel. If you try to send the glycerol into GNG to provide glucose for the brain, you need to rob glucose from somewhere else in order to continue to supply triglycerides for lipolysis.

Maybe it does work as you describe though if the lipolysis is from free fatty acids which maybe includes dietary fatty acids, eg in an isocaloric or hypercaloric diet.

Here is what Lyle MacDonald says about it in his excellent "Ketogenic Diet" book:

The glycerol portion of triglycerides (TG) is converted to glucose in the liver with roughly ten percent of the total grams of TG broken down (whether from bodyfat or dietary fat) appearing as glucose (25,29). An average sized individual (150 lbs) may catabolize 160-180 grams of fat per day which will yield 16-18 grams of glucose (10). Obviously a larger individual would oxidize more fat, producing more glucose. The amount of glycerol converted to glucose is fairly constant on a day to day basis and will depend primarily on metabolic rate.

Remember, in deep ketosis the brains requirement for glucose is reduced to just 25g a day...

 

[Spiker]

Ok but my point is that the glucose liberated from glycerol needs to be recycled into glycerol, or fatty acid transport out of adipose cells as triglycerides halts. So you can't oxidise this fat-derived glucose on a hypocaloric (or isocaloric?) ketogenic diet. Maybe you can oxidise the fat-derived glucose on a hypercaloric ketogenic diet, but that's not usually what we are talking about. Any time your fat is coming from adipose cells, it "costs" one glucose to get the triglyceride out of the adipose cell, so if you burn that glucose, you just create a glucose deficit. That glucose then needs to be found from somewhere else, otherwise you can't get more fat out of the adipose cells. Basically the glucose used to build triglycerides needs to be reserved for that function, and can't be oxidised.

But you can probably oxidise the glucose in free mono and dia glycerides coming in from the gut that never make it to adipose tissue in the first place.

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[mo1905]

Reckon we could get a team for Eggheads off this thread Any takers !


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