"This is a curious statement, Tom. The body has trouble whenever any nutrient is insufficiently provided for, no? The same could be said for carbs when in high intensity workouts... What happens when dietary carbs is inadequate? Hypoglycemia. I'm not sure what you are trying to get at by stating this."
Not really, Miguel. When carbs are exhausted in high intensity workouts, you either slow down or grind to a halt because you can't oxidize either fat or protein fast enough to provide the energy necessary to support the high intensity of your workout. This is something I have had a lot of experience with, and it happens long before you go hypoglycemic, a condition I have never experienced over many, many years of high intensity workouts. When glycogen stores are exhausted, the liver will provide glucose via gluconeogenisis to support fat metabolism. If it is not from dietary sources, it will come from muscle, and that is problematic. When both glycogen and fat are exhausted, energy will be supplied by metabolizing more muscle, and that is even more problematic. Protein is a special case, although losing the fat protecting the organs is also a serious matter.
"Why is there this assumption that the preferred state of being for a healthy organism is high intensity exercise? "
I made no such assumption. If you understood that from my post, I apologize for not being clear. I will say that high intensity exercise, properly used will enable you to perform well at lower intensity under demanding conditions such as high altitude. That is where it fits into my backpacking training. When I was racing seriously, high intensity training was mandatory if I was to remain competitive, but that is a special case that does not apply to the general population.
"Also, you assume that the "higher" and "healthier" state of being for human societies is civilization, as if hunter/gatherers somehow live in a lesser state of being. I'm not sure why you necessarily equate civilization with health. In almost all cases hunter/ gatherers that live their traditional lives tend to be far stronger and healthier than "civilized" equivalents. You have just to take a look at their bodies to see the effects of their lifestyles."
Again, I apologize if you understood that from my post. My feelings on the subject are decidedly mixed. I make no assumptions or value judgments about hunter gatherers' state of being other than that they, like the rest of us, take joy in their existence. I definitely DO NOT equate civilization with health or a healthy life style, although that is partially because we do not take advantage of the opportunities civilization offers us and partially because of the misuse of our knowledge. Optimally used, civilization could offer us the benefits of both worlds. All that said, hunter gatherers face a set of health challenges we do not, and are powerless in the face of the onslaught of "modernity". Their way of life is no bed of roses, and never was. I do not look upon them as "noble savages" or otherwise romanticize them, but view them as one more manifastation of humanity in all its diversity, and a reminder of the price we have paid for what we have achieved and misused so casually. As I said, for me it is a mixed bag.
"That's the thing. There has been a lot of inquiry into why diabetes happens in the first place and why it has become a skyrocketing epidemic in modern societies. Why, for instance, does the optimal lifestyle for a diabetic completely follow the optimal guidelines of the lifestyle for a non-diabetic person? Almost everything I have read points to diabetes being highest among people who ate the least amount of carbs before their lifestyles changed to modern diets. These are also societies that often sustained periods of famine. The theory now is that people prone to diabetes actually carry genes that, in a lifestyle of few carbs and intermittent fasting, helped them survive, because diabetics are prone to getting fat. Only in an environment of constant plenty, constant high calories, and unending access to carbs does diabetes arise. The coping/ survival mechanism that diabetes prone people carry within themselves was never meant to deal with the onslaught of over-nutrition that modern society allows. And the fact that there are so many people getting diabetes says something about the way we eat. Of course, the lack of exercise has a big part in this, too. But as Mark Sisson suggests in "Primal Blueprint", our health depends about 80% on nutrition and only about 20% on exercise."
I have no quarrel with what you say, but I do have this sense that exercise plays a larger part in the problem than Sisson claims. As for the unhealthiness of the modern diet, that is an individual choice. Nobody has to sussist on Big gulps and Doritos, etc, nor do they have to sit on their butts in front of an X-Box all day. I have seen too many people, of both sexes and all races and body types, who don't do that live extremely healthy lives. Those who have a genetic predisposition to diabetes are another matter, one that I am not competent to comment on, but everything I have read and heard from health care professionals leads me to believe that a large percentage of those who contract type 2 diabetes did so as a result of poor diet and lack of exercise.
"This is consistent with my above observation that perhaps a gentler form of keeping active and staying healthy is more natural. This constant drive to perform high intensity exercise is quite unnatural for most of our day-to-day lives. Perhaps we should learn something about long-term health and the problem with over-eating and over-training."
No quarrel with this statement, especially the overeating part, although on behalf of those of us who at one time or another in their lives have chosen the high intensity path as PART of their life style, I will say that it does have it attractions and rewards. Whether it is natural/healthy or not I will leave to individual judgment, but after years of weaving it into my life, I am still going strong at 71 with my knees, hips and ankles in good working order, as are many of my former compatriots. One thing you need to understand is that high intensity training is not, indeed cannot be, constant. It very quickly leads to breakdown. Like everything else in this life, moderation is the key to success.