So the usual fasting BG #'s for non-diabetics recommended by Bernstein and others down in the 80s may be too LOW, due to excessive production of insulin at some point during the day, and the body's barometer of what's "normal" getting out of whack? I would assume he would counter that insulin doesn't get produced at those low levels, so one should keep them down there as much as possible. This is still fuzzy to me. Can you explain in simple terms why he would be wrong on that? Could his analysis be skewed by dealing solely with people who eat at least some carbs? Is he allowing for higher-than-healthy post-prandial and random BG levels to get the fasting BG down to the 80s? Do you know the average post-prandial BG levels for zero carbers vs. carb eaters?
Here’s what I believe is going on and why “healthy” carb eaters would have a lower “fasting” BG. This is the world according to Lex and may be pure baloney so reader beware.
Remember that there is a ‘satisfactory’ range for most things. For blood PH the range is very tight – a range of about 7.35 to 7.45 – and the body will do whatever is necessary to keep PH in this range. For BG it is a much broader range – somewhere between 65 mg/dl to 110 mg/dl. As long as the BG levels are in the proper range the body will not do anything to raise or lower them other than the ongoing natural consumption of BG by the various BG dependent tissues.
Another variable is the digestion time of the food we eat. Simple and refined carbs digest in minutes and cause rapid spikes in BG, where fat and protein take hours to digest and are converted to BG at a much slower but sustained rate.
If BG falls too low then the body will initiate hunger and/or start sacrificing fat and muscle to bring the level back up. It will not create more than necessary as this would destroy tissue unnecessarily. An example might be when fasting. Only the amount of tissue necessary to sustain the body is sacrificed. This process of mobilizing tissue is a slow process so little insulin would be produced and BG would hover in the lower ranges with the body just adding to it as necessary to sustain BG just above the lower limit.
When we eat slowly metabolized foods like meat and fat, BG rises slowly as some amino acids as well as some of the glycerol from the fat are converted to BG by the liver. This is a very slow process and even though the food is gone from the stomach in a couple of hours, the slow conversion can sustain a slow manufacturing of glucose by the liver for many hours after a meal. As BG rises, it will reach the upper limit and then small amounts of insulin will be released to keep it just below that level. I find that 10 to 15 hours after eating my BG will then slowly fall until it reaches its low for the day, usually just before I eat my next meal.
In conjunction with the meat/fat scenario above, most of the tissues are using fatty acids rather than glucose. Now the body is calling on fat reserves between meals to provide fatty acids for muscles and other tissues that on a high carb diet would call for glucose. In the fat adapted person, the glucose isn’t needed and becomes somewhat of a waste product. The fat is mobilized from the fat cells as a triglyceride. When the triglyceride hits the liver, it is broken apart into 3 fatty acids and 1 glycerol molecule. The fatty acids are released into the bloodstream where they are consumed by fat adapted tissue. The glycerol, having no extra free fatty acids available to make up a new triglyceride, is converted to glucose (two glycerol molecules can be turned into one glucose molecule in the liver). This is new glucose that is released into the bloodstream and as there are few tissues in a fat adapted person to use this glucose, as BG rises to the upper limit, insulin is released to cause the conversion of glucose back into fatty acids. Again this will keep BG just below the upper level.
Finally we come to the high carb eater. Since most of the carbs we eat are refined and simple sugars, our bodies are not geared to the speed at which they are metabolized and released into the blood stream so the body overreacts by dumping more insulin than necessary because it thinks the rapid spike will last a long time. After all, all the other glucose producing mechanisms in the body do so over long periods and the body doesn’t know that the rapid rise will be short so it dumps insulin as though the spike will be sustained (relatively speaking). This over reaction causes BG to plummet to the low end of the scale and since carbs are metabolized quickly, there is nothing to raise it back up so it stays low. This is aided by the fact that muscle and other tissues are not fully fat adapted so will use glucose as their primary fuel if available so any glycerol or protein that is converted to glucose over the long term is rapidly consumed again keeping BG at the lower levels. If it gets too low then we are driven by discomfort, headaches, hunger etc to consume carbs to bring the level back up and if food is not forthcoming, the body will sacrifice fat and muscle tissue to create glucose.
In this case, fat is mobilized again in the form of triglycerides, and when they get to the liver they are torn apart into 3 fatty acids and a glycerol molecule. Now comes the difference. In the case of the carb eater, his body is demanding glucose, not fatty acids for fuel, so the liver will convert the glycerol into glucose and throw the fatty acids away in the form of ketones which are eliminated through urine, sweat, and breath. Since it takes 2 glycerols to make one glucose, two triglycerides are consumed and 6 fatty acids are thrown away for each molecule of glucose produced. This is why non fat adapted people loose weight rapidly. Their fat is being consumed to get at the glycerol to create glucose and 3/4s of the energy from the triglycerides (6 fatty acids) is being discarded. Only the minimum amount of tissue will be consumed as the body thinks it is starving so BG is again held to the lower end of the range. In effect, the high carb eater will have huge spikes of BG but they are short in duration (as long as the pancreas can produce enough insulin) so the body’s reaction will force BG to the low end for most of the day.
If this keeps up the body will slowly start converting tissues to efficiently use fatty acids and weight loss will slow. If we are fasting (not eating food) but have been eating a high carb diet then BG will remain in the lower range. If we are changing the type of food we eat then as the body becomes more efficient at using fatty acids rather than glucose as fuel, weight loss slows and then turns around and we start gaining weight again and BG will remain in the higher ranges because it is not needed by most body tissues.
Hope this made sense. If not ask questions and I’ll do my best to make it more clear.
This bodes poorly for the human race. Even conventional Paleo diets like Dr. Cordain's could not come close to feeding the world. What appears to be our natural carnivorous diet would feed far fewer.
I believe this is correct. Our planet could not sustain anything like it’s current population if we were eating our natural diet. I’m sure that this is what has driven our species to eat carbs in the first place. We had depleted our normal food supply and we had to find a new one or we would go through the natural cycles of population based on the available food supply like all other animals in nature do.
What do you think of the hypothesis of homonids, beginning to transform into super-hunters (meaning well beyond chimp abilities) around Austrolopithecus, coming to the fore with homo erectus, and becoming highly advanced with archaic homo sapiens, increasingly becoming super-predators and super-exterminators of megafauna, who had not adapted to intelligent, cooperating, tool-using primates hunting them as their primary food, and thus lacked fear of them and were easy prey, leading to the extinction of the majority of the megafauna? Instead of "Man the Hunter," it seems to be "Man the Carnivorous Super-predator." Have you expounded on this somewhere already?
I really have no interest in this area so your guess is as good as mine – and probably better.
Lex
