Carbohydrate Energy Paradox

[borofergie]

PART 2 - How Much Glucose do You Burn per day?

Although the precise magnitude of the various quantities is uncertain, it appears that the body's daily glucose consumption is about 150-480kcal for brain and nerves, 200-300kcal for glycoproteins such as mucin, 100 kcal for muscle glycogen and immune, intestinal, and kidney cell use, offset by about 200kcal produced in the course of fat burning. In elite athletes glucose needs are increased by 50 to 100 calories per hour of training.

For most people something like 400-650 daily glucose calories must be obtained from diet, manufactured from protein, or replaced with ketones.

So you use typically between 100 to 150g of carb a day - with an extra 15 - 25g per hour of athletic training per day. So your 600g carbohydrate bucket "leaks out" about 150g a day. If you eat more than about 150g of carbohydrate a day, eventually your "carbohydrate bucket" will overflow.

So basically your body can store about 4 days worth of glycogen.

Small amounts of glucose can be stored as muscle and liver glycogen. This is the healthiest, quickest, and safest way to dispose of excess blood glucose.

Glycogen storage capacity is limited to about 300 to 500g in skeletal muscle and 70 to 100g in the liver. Glycogen stores are never allowed to become fully depleted (unless one "hits the wall" in a marathon), and so glycogen resevoirs can rarely accomodate much extra glucose.

High-intensity exercise depletes glycogen, so elite athlets can safely dispose of a big bowl of rice. But ordinary people who eat a high-carb diet will tend to keep their glycogen resevoirs full. In practice their disposal mechanism is probably limited to a few hundred calories at most.

If you eat more carbohydrates than you burn, within a pretty short time you'll fill up your "carbohydrate resevoir" and your bucket will overflow. In practical terms, this means that your metabolism will invoke some additional disposal pathways.

 

[borofergie]

PART 3 - Disposal Pathways

1. You can fill your liver and muscles, if they have been depleted through exercise
2. You can convert the carbohydrates to fat, through a process called de novo lipogenesis
3. If your BG levels become dangerously high your pancreas will secrete more insulin to try and force your that normally burn fat to burn glucose instead. This so called "Direct Metabolism of Glucose" creates reactive oxygen species which damage the cell, and switches it to metabolic pathways characteristic of cancer and diabetes (YAY!) Jaminet says "Ideally most cells should never metabolize glucose directly, they should obtain all of their energy from fats or from glucose-6-phosphate, peeled off in a controlled way from glycogen."
   
4. You can store a small amount in your blood through chronic hyperglycemia. We all know how bad that is.

There Are No Good Glucose Disposal Pathways:

Above the body's daily glucose needs, which we earlier estimated at 450-600kcal, there are no healthy ways to dispose of excess glucose. The healthier disposal pathway, conversion to fat, is slow, so high-carb eating inevitably leads to elevated blood sugars and resulting glucose toxicity.

One is always better off stopping glucose consumption at the limit of bodily needs. Consuming saturated fat instead of carbs reaches the same endpoint, but without the intermediate toxicity from elevated blood glucose.

It's healthier to eat fat than to eat carbohydrates that get converted to fat.

So, it's desirable to eat no more carbohydrates than your body can use. Glucose-to-fat conversion begins somewhere around intakes of 500 to 600 carb calories per day. Beyond that level, carbs become an unhealthy source of calories.

 

[borofergie]

In Summary

Your metabolism only burns around 160g of glucose per day. If you eat more than that, you'll fill up your glucose resevoir (liver and muscle) and your body will have to turn to alternative disposal pathways, either by creating fat, forcing your cells into burning extra glucose, or letting your BG get high.

This matches our emprical observations on this forum. We typically observe that Grazer is the "highest carber" of the diet controlled T2s and he eats about 160g of carb per day. Most of us, with more damaged endocrine systems, eat a bit less.

 

[librarising]

Very informative.

I will be returning to take this in when I'm less busy.

Cheers for that :thumbup: :thumbup: :thumbup:

Geoff

 

[lucylocket61]

Thanks for the explanation borofergie I like to know why I am doing something, as well as what to do.

 

[xyzzy]

Great series of posts Stephen thanks.

 

[borofergie]

All this is saying is that, if you are going to eat more than about 160g of carbs a day, you'd be better off eating the extra calories as saturated fat.

If you are going to overfill your "glycogen resevoir" by regularly eating more than 160g of carbohydrate, the best possible thing that can happen is that the carbs will be turned to saturated fat, probably increasing your BG level, and possibly leading to direct metabolism of glucose (which may lead to cancer or diabetes*).

Note, that just because you are creating fat from excessive carbohydrate doesn't mean that you are storing it. It's just the same as any other fat in that you can burn it to meet the rest of your energy requirement.

*At least none of us have to worry about catching the diabetes.

 

[phoenix]

I really don't think that there is any evidence to a maximum amount of glucose that can be processed in a healthy metabolism; as long as the total energy intake doesn't exceed calorific needs. The human metabolism is adaptive. If a person eats a high carbohydrate diet, glucose oxidation pathways are stimulated. Jecquier mentions both increased glucose oxidation after carbohydrate overfeeding and the capacity of glycogen stores increasing.
Undoubtedly glycogen stores have a maximum capacity but this only when there is a chronic increase in energy intake. Even then when lipogenesis takes place it takes a lot of energy to convert CHO to fat , it isn't a direct calorie for calorie conversion.

The opposite happens when someone eats a higher fat diet, glucose pathways are down regulated.

I'm not sure that Jaminet himself is so certain

Well, as my “Carbohydrate and the Thyroid” post discusses, how much glucose we utilize is a little unclear. 600 to 800 calories/day is a reasonable guess, but it can be elevated during infections such as fungal infections.

http://perfecthealthdiet.com/2011/08/po ... nny-roddy/

In the post he refers to he says.

Because limited research has been done on this subject, it’s possible that we’ve underestimated the body’s glucose needs. It could be as high as 800 glucose calories per day. It’s not likely to be lower.

This is for sedentary healthy people. Two factors may substantially increase glucose utilization:

Infection. Many pathogens consume glucose – indeed, people with parasitic infections can sometimes have great difficulty obtaining enough glucose from food – and the immune system also consumes glucose.
Athletic activity. Exercise can consume large amounts of glucose.

http://perfecthealthdiet.com/2011/08/ca ... e-thyroid/
Actually, it's a very interesting post, From what I can gather he doesn't count vegetable sources of glucose so these would be in addition.

and just a fuller explanation from Chris Kresser which points to the body normally being able to process far more than 160g of glucose

The argument is that starch is not safe for healthy people, I would say there’s little to no scientific or anthropological evidence to support that idea, and overwhelming evidence opposing it.
There are literally billions of people eating high-starch diets worldwide, and you can find many examples of cultures that consume a large percentage of calories from starch where obesity, metabolic problems and modern, inflammatory disease are rare or nonexistent. These include the Kitava in the Pacific Islands, Tukisenta in the Papa New Guinea Highlands and Okinawans in Japan among others. The Kitavan diet is 69% carb, 21% fat, and 10% protein. The Okinawan diet is even more carb-heavy, at 85% carb, 9% protein and 6% fat. The Tukisenta diet is astonishingly high in carbohydrate: 94.6% according to extensive studies in the 60s and 70s. All of these cultures are fit and lean with low and practically non-existent rates of heart disease and other modern chronic disease.
Amylase is thought to have played a key role in human evolution in allowing humans an alternative to fruit and protein. Compared with primates, humans have many more copies of a gene (AMY1) essential for breaking down calorie-rich starches. The ability to digest starch, along with the discovery of fire and cooking, gave humans a new food source that allowed us to thrive even in marginal environments. Some scientists have even argued that consumption of starch, along with meat, was primarily responsible for the increase in our brain size

http://chriskresser.com/is-starch-a-ben ... or-a-toxin

 

[Etty]

There may be different effects on health from eating a 69% carb diet like the Kitavans compared to a 69% carb diet as eaten by Westerners. The Kitavans lived on gloopy cassava porridges and such made from local tubers. There was virtually none of the grains and refined sugars that make up so much of the western carb load. Also, their fats were different, with 17% saturated fat and little vegetable oil. In the West, we are urged to reduce saturated fat below 10%, and vegetable oil is in everything. Their omega3-6 balance was better. There was virtually no processed food. And they were "moderately" active. There would be less environmental pollution in their air, water, and food. Their lifestyle was likely less stressful.
Americans would probably be healthy on such a diet in such a food environment. But in their present environment, they may be wise to reduce carbs.

 

[borofergie]

Said it before, without grains or sugar there'd be very little obesity or T2 diabetes (and maybe not much T1 either).

Jaminet, Kresser, Harris and Guyenet would probably all agree that eating some "safe" starch from tubers probably isn't too bad a thing if you aren't metabolically deranged (ie diabetic). They'd also agree that eating a diet that is largely based on grains, grain products and other refined carbohydrates is almost certainly deleterious to your health. (Kresser thinks that grains are not worth the effort at all).

If I wasn't diabetic, I'd be getting my 160g of carbs a day from sweet-potatoes, just like Jaminet and every Paleo cross-fitter suggests. This is entirely consistent with Jaminet's 160g of carbs a day theory. If you cut out grains and sugar then you're going to have a hard struggle getting above 160g a day, unless, like the Kitavans, you are scoffing copious amounts of yam and sweet potato.

Like Dr Kurt says: "If you have the choice, why choose corn or potatoes over meat?"

Between the Zero carbers and the Kitavan cult, I feel a bit squeezed.

Over and over I say that the 10- 30% range for carbs sounds reasonable for most people.

Prove to me that 60% is better than 30%. Or at least make the argument. I would do it for you if I could, but I cannot even imagine how it would be constructed. Otherwise please stop perseverating on the Kitavans until a study comes out with something new.

http://www.archevore.com/panu-weblog/20 ... avans.html

 

[viviennem]

"Metabolically deranged", huh?

I like it, Borofergie! All the rest of me is pretty much deranged - good to know my metabolism is following the trend! :lol: :lol:

Viv 8)

 

[maddiemo]

If I eat any grain what so ever I feel so ill, and drop off to sleep all over the place when I went for my gloucose intolerance test I had to wait in the surgery I told the nurse I will fall asleep. She said she had to laugh because when she walked pass I had the book on my lap looking down and fast asleep. I have cut down on carbs about 60g a day and now I stay awake all day. I just can't tolerate them at all. If I have a couple of potatoes my BG goes high. Oh and the surgery was full :lol:

I haven't bothered to see the diabetic nurse because I know what diet she will put me on. HIGH CARB!!!