In answer to the question, "Is a Paleolithic diet the best diet for longevity?"..
As a doctor that has been promoting a high-fat, low carbohydrate, and restricted protein diet for almost 2 decades, I have long been saying that one cannot use paleolithic nutrition as a basis to determine optimal diet. Although a paleolithic diet may not be a bad diet and often is good(depending on which paleolithic diet one is talking about), the entire premise of using paleolithic nutrition as a basis to obtain an optimal diet is flawed.
Nature is concerned about reproductive success, not about significant post-reproductive health and lifespan. In other words, nature really doesn't give a whit about how long we live unless it pertains to reproductive success. Therefore, we cannot look to nature or count on nature or what's “natural” to tell us how to live a long healthy (post-reproductive) life. To obtain an optimal diet (as opposed to just a better diet that would be virtually any diet that deviates from the standard American diet) one must use modern science that one could even consider to be “unnatural”. (See short excerpt from my book below.)
The science of insulin and leptin clearly reveal that a diet high in non-fiber carbohydrates is extremely unhealthy and shortens lifespan. Furthermore, considerable and robust science tells us that excess protein (any protein beyond that necessary to build, repair, and maintain oneself) is equally detrimental (see links below to a couple of PowerPoints of talks I have given). Oil and fat is really the only relatively safe fuel to burn, and ones diet should consist mostly of this along with the necessary protein and minimal non-fiber carbohydrates, whether or not this sort of diet was paleolithic.
From p.46, "The Rosedale Diet" © HarperCollins
■ LONGEVITY ISN’T “NATURAL”
"Within the billions of years that life has evolved on earth, we may have become smarter, more complicated creatures than our single-celled predecessors, but the fact is, we are here for pretty much the same reason. As Mother Nature sees it, whether you are a single-celled organism, a multicelled nematode, a bird, a dog, a cat, or a human, you are here for the primary purpose to reproduce and pass your precious genes (the library of life) on to the next generation. After that, you’re expendable. My patients are shocked when I tell them that there is nothing “natural” about trying to live as long a life as possible. You may want to hang around to be a healthy 120 and spend your last decades playing with your great-grandchildren, writing your novel, or traveling the world, but Mother Nature has other ideas. Mother Nature’s primary concern is to keep you alive long enough to reproduce, and maybe a bit longer after that to care for your young. That’s it. Some scientists believe that our cavemen ancestors followed an ideal diet for our health and longevity because they ate the “pure” and “natural” diet that we all evolved from. In reality, the so-called “paleolithic diet” followed by cavemen was not necessarily ideal for long-term health; in fact, it was sort of random. Cavemen ate whatever Mother Nature made available to them at the time. Keep in mind, Mother Nature didn’t give a whit about eating for a long healthy life; she just wanted cavemen to make more baby cavemen. You see why I say there’s nothing “natural” about the quest for longevity? If anything, in order to achieve longevity, you have to circumvent Mother Nature and consider some “unnatural” alternatives. By that I mean you have to “trick” Mother Nature at her own game.
Nature has very ingenious ways to help a species survive. When food is scarce, as it often was for our more primitive ancestors, in order to ensure the survival of a species, nature developed a method of keeping an organism alive through times of famine so that it could reproduce at a later, more opportune time. Reduced food intake turns on genes that protect the body against aging, allowing it to hopefully outlive the famine. Instead of spending lots of scarce energy to make babies that couldn’t survive, the body focuses its energy on maintaining and repairing itself. As soon as there is enough food available to support effective reproduction, the body switches gears and reduces its emphasis on maintenance and repair and directs its energy toward reproduction.
When you are in maintenance and repair mode, the body’s “body shop” is revved up and ready to go. Calorie-restricted animals have measurably higher levels of key chemicals that allow for extended life, protect cells from damage, and promote repair.
You don’t have to starve yourself to turn on the maintenance and repair switch. Following the Rosedale Diet will do the same good things for your body. How does it work? Leptin is a key player (perhaps in concert with insulin) in the evolutionary tug of war between whether the body should concentrate on reproduction or maintenance and repair."
...and to live a long, healthy, post-reproductive lifespan, we want our bodies to concentrate on maintenance and repair. To do that we must use modern science that tells us that we must regulate the hormonal nutrient sensors that, when kept low, turn up the genetic expression of maintenance and repair.
My comments to Stephan Guyenet responses to my answer on his site Dec. 4, 2009
Dr. Ron Rosedale said...
Pertaining to insulin's primary purpose:
Again, we must distinguish between controlling blood sugar and lowering blood sugar in a "normal" individual. Yes, I am well aware as are most people, that insulin can lower blood sugar. It does not mean, however, that insulin is controlling it. It is lowering the glucose levels as a side effect secondary to storing it as glycogen (little) and fat (lots), not to control the serum levels as we were typically taught in med school. The immediate regulation of blood glucose is left to epinephrine, norepinephrine, cortisone, glucagon, hGH, all of which control it in an upward direction primarily to make sure there is an anaerobic fuel available for emergencies. Just as we would not send a man to the moon with just one mechanism to deliver O2, we have many mechanisms to increase glucose, not lower it. This may be a very good clue of our evolutionary priorities. Furthermore, as far as glucose levels are concerned, a major role that insulin plays is to inhibit gluconeogenesis that would otherwise raise glucose by default, as seen in type 1 DM, as well as type 2, i.e. why they wake up with high BS even after fasting 10 hours. This may even be more to preserve lean mass than concern about high glucose levels in a normal, non type 1 DM individual. Also, I doubt there were enough type 1s in our evolutionary history for nature to give a whit about. Granted, however, that extremely high BS leading to spillover in the urine and dehydration as typically seen only in an uncontrolled type 1 diabetic along with severe acidosis would be selected against with relevance determined by the number of these individuals. Pertaining to all others with elevated glucose;: type 2 diabetics, impaired glucose tolerant individuals, anyone shortly after eating a typical breakfast of cereal and orange juice, etc.; the chronic diseases associated with this (i.e. all the chronic diseases of aging) including CAD and cancer afflict most people after having reached reproductive maturity. Even relevant parenting (especially in our ancestral history when reproduction was likely at an earlier age…) lies beyond evolutionary selective pressure. Thus elevated glucose would not have had great pressure to be selected against and may even have conferred advantages. Type II diabetes may therefore be an example of "antagonistic pleiotropy".
Insulin's primary, evolutionary role was established billions of years ago—long before glucose was a significant part of our diet. Insulin in found in virtually all animal life, "down" to worms and yeast (where it also takes on IGF functions). It was certainly not used to lower blood glucose levels.
January 7, 2010 11:56 PM
Dr. Ron Rosedale said...
Thank you for your comment about leptin. I am also aware of leptin and its role in centrally regulating glucose, insulin, and most of the hypothalamic functions... I have written a book on this.
Pertaining to maintenance and repair:
The energy required for basal metabolic rate should almost entirely go to "maintenance and repair" such as the maintenance of body
temperature, the maintenance of heart rate etc. Also, you mention
moving muscles. Whenever that is accomplished, it damages the
muscle and there must be repair of that muscle.
I will quote from the recent article published in the journal Nature out of Linda Partridge's lab that you mentioned:
"It [calorie restriction] is widely assumed to induce adaptive reallocation of nutrients from reproduction to somatic maintenance, aiding survival of food shortages.”
-From: "Amino-acid imbalance explains extension of lifespan by dietary restriction in Drosophila", Nature, Dec 2, 2009.
That was my assertion...that it is a popular and widely accepted (even "assumed") theory.
Reproduction vs. maintenance and repair derives from Tom Kirkwood's very popular "disposable soma" theory...
I think that the major point is being missed. I am talking about care and repair of the genome vs. its reproduction. The soma (body) is to take care of the genome until it can be reproduced and until it is environmentally/nutritionally advantageous to do so. Therefore all energy that goes into maintenance of the soma, whether that be for individual cells (outside of the nucleus) or the body of cells, until the genome can/should be reproduced, is energy for maintenance and repair. This allocation was apparently established during oceanic single celled life billions of years ago.
Even so, the fact that M&R and reproduction are linked does not imply that it must be... the fact that it may be possible to unlink them does not mean that they were not linked or are not naturally linked…
As far as Kitivans are concerned, one can debate all one wants about what ancient man ate or current societies eat... and it gets you no closer to determining the optimal diet (excepting that they may indicate what not to do). Diets evolved for reproductive success—not long, healthy, post repro life... for that we have no footsteps to follow.
January 7, 2010 11:58 PM