Fructose - an alternative view (light hearted)

[LittleGreyCat]

Fructose is generally demonised because it is not metabolised like glucose, but instead it goes straight to the liver where it is processed and stored as fat.
Nobody wants a fatty liver, right?

Assume that I am in ketosis, that is running on ketones because I'm not eating many carbohydrates.

(1) Fructose doesn't raise BG
(2) Fructose gets converted to fat
(3) I'm running on fat

Leaving aside the extra energy needed to process the Fructose, what's not to like?

No doubt there are sound reasons for this not to be as simple as stated.
Otherwise pure Fructose could be an alternative sweetener.

 

[lovinglife]

But the fat stays in your liver - fructose is the main cause of NAFLD, you may be interested in this @LittleGreyCat

The negative and detrimental effects of high fructose on the liver, with special reference to metabolic disorders

The increased consumption of fructose in the average diet through sweeteners such as high-fructose corn syrup (HFCS) and sucrose has resulted in negative outcomes in society through producing a considerable economic and medical burden on our healthcare ...

www.ncbi.nlm.nih.gov

 

[LittleGreyCat]

But the fat stays in your liver - fructose is the main cause of NAFLD, you may be interested in this @LittleGreyCat

The negative and detrimental effects of high fructose on the liver, with special reference to metabolic disorders

The increased consumption of fructose in the average diet through sweeteners such as high-fructose corn syrup (HFCS) and sucrose has resulted in negative outcomes in society through producing a considerable economic and medical burden on our healthcare ...

www.ncbi.nlm.nih.gov

That is my point, though.
If you are using your liver as an organ for burning fat, then having fat in your liver is just another available fuel source.

NAFLD is something which you have, as I understand it, when you are not burning up available fat reserves.

If you are over weight and go onto low carb/keto then this can significantly reduce the fat around your organs, including in your liver.

So my point is, we know Fructose can be a bad thing if you aren't burning fat though your liver.
However if your liver is a mean, lean, fat processing machine it will presumably also process the fat from the Fructose.
One cure for NAFLD is LCHF, as far as I understand it.

 

[lovinglife]

But your body doesn’t use the fructose as energy, only your liver can process fructose, nowhere else in your body can,

Fructose and fatty liver – why sugar is a toxin - Diet Doctor

Fructose is even more strongly linked to obesity and diabetes than glucose. From a nutritional standpoint, neither fructose nor glucose contains essential nutrients. As a sweetener, both are similar. Yet fructose is particularly malevolent to human health compared to glucose due to its unique...

www.dietdoctor.com

Edited to correct spelling

 

[KennyA]

That is my point, though.
If you are using your liver as an organ for burning fat, then having fat in your liver is just another available fuel source.

NAFLD is something which you have, as I understand it, when you are not burning up available fat reserves.

If you are over weight and go onto low carb/keto then this can significantly reduce the fat around your organs, including in your liver.

So my point is, we know Fructose can be a bad thing if you aren't burning fat though your liver.
However if your liver is a mean, lean, fat processing machine it will presumably also process the fat from the Fructose.
One cure for NAFLD is LCHF, as far as I understand it.

I don't think our livers "burn fat". As I understand it, the body's main fuel users (whatever the fuel) are muscles and the central nervous system. The liver is the only organ that can digest/process fructose, and excess is stored in the body as fat.

If you take your argument a step further, then all body fat, visceral and sub-cutaneous, is "just another available fuel source". The point is that storing surplus sugar intakes as bodyfat causes rather a lot of problems as outlined in the research quoted above. Fructose is just rather more difficult for the body to manage than either glucose or sucrose.

Having been there and having had some of the associated problems, I have no intention of doing anything that might lead to me again storing visceral fat. And I've pretty much been in constant ketosis for the last five years.

 

[Lamont D]

This is one thing I have never researched about RH.
Maybe, there isn't any done.
Not thought a lot about till before,
Maybe someone can answer this.
Pre diagnosis, I was mistakenly diagnosed as a fatty liver. By I had NAFL.
I was misdiagnosed as T2, due to results from a hba1c test.
As bad as the recommended dietary advice regarding carbs, I was told to keep eating fruit.
An apple and some fresh citrus. Maybe half a banana. For the usual reasons.
But pieces through the day.
Since diagnosis, my NAFL went away, even though I still had up and down function tests for the liver.
My non diabetic fasting levels and the health of my organs improved rapidly as did losing the weight.
Of course, having continuous normal BG levels, meant no hypos. No reaction to fresh food.
But I could fast for days, without effect, and my energy levels increased.
My energy levels are excellent, I don't have lethargy, tiredness or the usual symptoms of a metabolic condition.
On a long fast, where does this energy come from?
I know about the keto diet and how it works.
So I have to do the normal day to day chores, I play with my grandkids, I have a long day. Looking after my wife.
But doesn't my liver help with glucogenisis (liver dump) for more energy, when I do too much?
I have always believed that it is a natural process, even through keto.
I still have pieces of fruit, where does the process of getting the minerals and such into my system?
Or is it individual, like so much in these conditions?

 

[LittleGreyCat]

But doesn't my liver help with gluco(neo)genisis (liver dump) for more energy, when I do too much?

This whole area is confusing.
If you are fasting then you should be in ketosis, and burning ketones which your body produces as an alternative fuel to glucose.
In that case why would you need glucose from your liver for extra energy?

In the keto world (as I understand it) the gluconeogenesis is required to produce the small amount of glucose which is required by parts of the brain which cannot access ketones because they can't pass that particular blood/brain barrier.
I don't think that it is there as an emergency energy store should you run low on ketones, but I could be wrong.

I intend to start another topic on processing of glucose when you are fat adapted and in ketosis, which may well overlap with this thread.

 

[zand]

When I am I ketosis for any length of time my FBG gradually rises. I always assumed this was from a small liver dump which my body doesn't/can't use while I'm fat adapted...? I think there was a thread somewhere about FBGs rising when doing keto.

 

[Lamont D]

This whole area is confusing.
If you are fasting then you should be in ketosis, and burning ketones which your body produces as an alternative fuel to glucose.
In that case why would you need glucose from your liver for extra energy?

In the keto world (as I understand it) the gluconeogenesis is required to produce the small amount of glucose which is required by parts of the brain which cannot access ketones because they can't pass that particular blood/brain barrier.
I don't think that it is there as an emergency energy store should you run low on ketones, but I could be wrong.

I intend to start another topic on processing of glucose when you are fat adapted and in ketosis, which may well overlap with this thread.

Yeah, I agree with your synopsis.
The thing about glucose for the brain does make sense. And this is why many doctors and medical profession insist that we need carbs, for solely that purpose cos of the ketones not being able. I think, tho some are just told we need carbs and that is it. Without the evidence to the contrary.
And we need carbs for brain function.
Why?
As I'm carb intolerant, carbs if I have them, I do get brain fog.
Pre diagnosis, I have lost so much memory and I could hardly think straight, which was as I researched, one of the major symptoms of rapid highs and lows of BG levels. The hypos, the spikes from morning to night.
Because of this obsession with doctors, dsns etc with having carbs.
And it was the carbs, that was causing RH symptoms.
And I was still being told, despite my health improvement, to have the carbs.
So, is it right? That has been proven why glucogenisis is for brain or as well as organs perhaps in ketosis.
I feel great fasting, even better than after low carb meal?
One of the symptoms I use to get, after food was hunger, why?
Could it be, that as I get older, I start having an aversion to food?
But I believe it's psychological.
My brain wanting high BG levels.
Im never hungry when fasting!!!

Not often discussed is the effect of your gut biome. The enteric system.
Some specialists even call it the gut, brain, trigger.
I have heard that the gut has brain cells, sending signals back and forth and to the pertinent organs, stomach, glands, intestines and so on.
I have to have meds, when required, that are sugar free, lactose free, enteric tablets.
So they are not dissolved in the stomach. I think.
What bearing does stomach acid have on the rest of the system?
So many questions.
So much we think we know.
Always trying to understand.
Why are we so similar but so individual!

 

[KennyA]

Bear in mind that there are less than 5 grams of glucose in the bloodstream at normal levels. My understanding is that this is a constantly changing dynamic rather than a static situation. A lot more can go wrong with this sort of setup - it might all produce the same elevated blood glucose, but that doesn't to me necessarily imply that the cause is the same.

Glucose is constantly moving into muscle stores, or being used for energy, or being created by the liver or digested from food, before we get to surplus glucose being converted to fat. So the levels will vary as (eg) muscles and CNS use glucose for energy, and as the glucose level is set and maintained by the liver via glycolysis.

This link (to a Michael Eades piece) explains further.

A spoonful of sugar - Protein Power

Whenever I give a talk and make the statement that a normal blood sugar represents less than one teaspoon of sugar dissolved in the blood, I'm often met with

proteinpower.com

As Eades says, the difference between having a normal blood sugar and a diabetic blood sugar is about a quarter of a teaspoon of sugar.

 

[HairySmurf]

The notion that all fructose is metabolised in the liver has been disproved, first paper on the subject published in 2019 - Link - where it was disproven in mice. Other studies have followed which support this.

Relatively low/slow doses (like a piece of fruit) are primarily metabolised in the intestinal wall and the fructose is mainly converted to other carbohydrates - primarily glucose and lactate. Higher/faster doses (like a sweet drink) appear to overwhelm the capacity of the intestine to metabolise fructose and in that circumstance the excess does appear to reach the liver.

If it reaches the liver is it primarily converted into glucose and lactate again, same as in the intestine - Link - the amount that is converted directly to fat is small to the point that no study has figured out exactly how small it is - Wikipedia says 1% - Link - but the paper linked above suggests maybe less than that.

Fat in the liver doesn't stay there. The liver pumps out fat all the time in the form of VLDL particles (roughly equivalent to blood 'triglycerides'). Liver fat is a problem if it builds up due to more fat being stored in the liver than is exiting it over time. There are several ways that can happen.

Fructose is indeed a fatty-liver causing problem in big doses, and drinking sweetened soft drinks in large quantities is a bad idea for anyone. Eating a moderate portion of fruit though is not. In low/slow doses the fructose in fruit is no different to any other carb.

 

[lovinglife]

The link I posted from DietDoctor says eating a small amount of low carb fruit compared to drinking and using fructose as a sweetener compares it to hitting your liver with a needle with the fruits or with a hammer with the drinks & sweeteners, which I think is a very good analogy.

A few berries every now and then isn’t going to do any harm but bombard your liver with fructose from corn syrup etc isn’t going to be good for you

I’m happy to leave the testing to the mice, I’m a human

 

[Lamont D]

Since this thread started, I have reduced my fruit portion intake daily.
I never thought I would ever.
I would have a small apple every day, not since Monday.
Don't know what effect this will take, I'll let you know.

 

[LittleGreyCat]

The notion that all fructose is metabolised in the liver has been disproved, first paper on the subject published in 2019 - Link - where it was disproven in mice. Other studies have followed which support this.

Relatively low/slow doses (like a piece of fruit) are primarily metabolised in the intestinal wall and the fructose is mainly converted to other carbohydrates - primarily glucose and lactate. Higher/faster doses (like a sweet drink) appear to overwhelm the capacity of the intestine to metabolise fructose and in that circumstance the excess does appear to reach the liver.

If it reaches the liver is it primarily converted into glucose and lactate again, same as in the intestine - Link - the amount that is converted directly to fat is small to the point that no study has figured out exactly how small it is - Wikipedia says 1% - Link - but the paper linked above suggests maybe less than that.

Fat in the liver doesn't stay there. The liver pumps out fat all the time in the form of VLDL particles (roughly equivalent to blood 'triglycerides'). Liver fat is a problem if it builds up due to more fat being stored in the liver than is exiting it over time. There are several ways that can happen.

Fructose is indeed a fatty-liver causing problem in big doses, and drinking sweetened soft drinks in large quantities is a bad idea for anyone. Eating a moderate portion of fruit though is not. In low/slow doses the fructose in fruit is no different to any other carb.

Thank you.
I am still working my way through the links but it is all very educational.
Yet another simple explanation (fructose goes straight to the liver) being questioned and probably disproved.
2019 is recent in information flow terms so no doubt it will take many years for this research to become mainstream.