Carbohydrate Energy Paradox

Jaminet said:

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.

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Jaminet said:

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.

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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.

Jaminet said:

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.

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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.

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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.

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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

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Kurt Harris said:

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.

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