He is flat out wrong on this one, Miguel.
Ach, Tom, isn't that rather harsh considering that the words above are mine, and only an interpretation of what Mittleman wrote? Take the information I wrote in context. If anyone was flat out wrong, it would be me, both in inadequately explaining what he wrote, and in my own incomplete understanding of the process. Keep in mind that, as I have frequently stated in my many posts on this topic, that I am still learning and have only a rudimentary understanding of all this. I post a lot because I am excited about what I am learning, but I am definitely not, and do not consider myself, an expert on any of this. You definitely have a lot more knowledge of the biochemistry than I do, and so what you explain helps me learn more and to change with new knowledge. I am perfectly willing to listen to what you have to say and to evaluate what I think I know, with my own experience and to alter my thinking if I think it properly challenges what I think I know. You obviously make the effort to understand all this, doing the hard work to learn about it. However, I will neither take seriously nor listen to anyone who hasn't done their homework. My main point in being somewhat adamant about the whole paleo thing is that people take the time to read and listen to lectures and such about the subject, before judging it or condemning it. Reading about it and understanding it is not the same as accepting it. And I've more than done my homework. I still have a very long way to go.
(Read one of the biggest voices in the paleo movement, someone who is most definitely not a "purist" and is severely critical of anyone who mindlessly follows the dogma without critical analysis and common sense: Free the Animal. This article in particular might be of interest. It's a good indicator of what the paleo community is like...)
I do understand that carbohydrates are absolutely necessary for one's metabolism. Not only do I understand this through what I've read, but viscerally, in my dealing with diabetes everyday. I have to take two types of insulin... basal and bolus. Basal insulin is the same as the underlying insulin that is present constantly in all of our bodies, the insulin that allows carbohydrates to metabolize and which in turn also kick start the metabolism of fats. Bolus insulin is the insulin that I shoot before meals, when my blood sugar will spike with any carbs I ingest. For normal people it is equivalent to the reaction of the pancreas when carbs are ingested and insulin is released into the bloodstream to both process the carbs into glucose and fat, and to counter the toxic effects of too much sugar. Without carbs, fats cannot metabolize (and this, as you explained, also has to do with the processes of the liver). So if I gave the impression that I think all carbs should be eliminated, I definitely was not explaining myself very well.
It didn't. Fat is definitely a far more efficient way to store energy, critical in fact to any mobile organism. Only plants store their main energy supply as carbs, because they don't move around. But that is not the whole story. The 2 are designed to operate in tandem.
I think that's exactly what I was attempting to say. I never said the carbohydrate burning system was not used. The explanation you give afterwards, is exactly what I've been trying to say all along, that for most of our activities, including most low to medium level hiking, the fat-burning system is far more efficient and far, far longer lasting (we have about 2,500 kcal of energy stored as sugar, but about 130,000 kcal of energy stored as fat). That 18 to 20 mile glycogen burnout you talk about is just that, a short term burst of energy that was not meant to be used most of the time.
I'm thinking hunting, being hunted, or combat here. Far from being emergencies, these situations were an everyday part of early human life.
On this I would very much have to disagree with you. I don't know where American male ideas of early human or present-day wild animal life come from, but there is this romantic element of the macho male fighting off rabid bears and wolves. Sure, occasionally, but not an everyday, 24-hour-a-day occurrence. People (and animals) had/ have to constantly be on guard, yes, but if the emergencies happened as often as you suggest, children would never have grown up and things like trees and such things a very delicate butterflies and crane flies would never survive long enough to make it to adulthood. By and large the daily life of wild animals was/ is quiet and uneventful. It is not at all like a war zone. If any of you actually spend as much time in the wilds as this site represents, then you know this to be true. Even in bear country as wild as Andrew Skurka's last big trip, he did not unendingly fight off bears and wolves. It explains why creatures such as platypuses and dolphins often die of stress from the overly loud noises humans make. In the same manner that constant stress even to our species today often causes many people to get very sick, so our bodies were not meant to be subjected to and did not develop in an environment of unending fight-or-flight stressors. Our use of the sugar mechanism was not meant to be turned on all the time... our bodies cannot handle that much constant adrenaline. The sugar mechanism, when used as the sole energy source, was only meant to be used for those fast 18 to 20 miles and only occasionally, because that was all that was necessary. We are not like hummingbirds, needing to burn sugar all the time. If we had needed to use such energy all the time, we would have developed it. Instead we developed an extremely efficient fat-burning mechanism. I don't think, in the advice given to people who need to lose weight and in our understanding of what constitute health and even everyday fitness, we're properly understanding and addressing the difference between these two systems.
That's how I'm beginning to see it anyway.
Now here is the part I'm still trying to get my head around, and which both Stu Mittleman and Dr. Phil Maffetone (Mittleman has run more than 300,000 miles as a professional ultramarathoner and has worked with thousands of clients, as a coach, while Phil Maffetone is one of the most respected sports doctors in the world) spend more than half of each of their books explaining. If, as you say, I am wrong about my understanding of what they say, why does the body have two different types of muscles, one anaerobic, the other aerobic, and why do they work differently... either utilizing the stored fat, or utilizing the sugar in the blood? And why is there a measurable difference (using a carbon dioxide/ oxygen analyzer for a gas-exchange analysis... more informative about fat burning and sugar burning than a V02max test... it's the test Mittlelman and Maffetone both use) in the amount of oxygen and carbon dioxide released in the breath, always corresponding to the intensity of the exercise and the type of food the subject predominantly eats? As two practitioners who definitely know the science behind their stuff and have had many years of experience working with this, I tend to favor what they say over what, forgive me if I come across as disrespectful, you might say, Tom. But I, personally, cannot argue any more deeply about the biochemistry; I simply don't have the background or the knowledge. It could be that I completely misunderstood what they were writing.