Calorie restriction is quite intriguing, but in the end run, we will find a few things that make it of limited value, including the fact that we now have 68% obesity and overweight, in this country. We can’t even get to near ideal weight and now we are to tell people to restrict well below their needs, for that?
So first, it is nearly impossible for most people to do. That does not make it “wrong”, it simply makes it impractical. You might think the promise of health and longevity would be enough, to get people to do some things on a habitual basis, to extend those qualities. Generally speaking, those promises are not enough. In point of fact, food is one of the main entertainments people have and entertainment seems to be far more important, to most people, than health and longevity, as witnessed by the fact they will spend thousands on cell phone apps, cable TV channels they never watch and countless non-productive hours on “social” networking, where no one actually meets face to face!
Second, as nearly we can tell from nutritional anthropology, our Paleolithic ancestors were not, as a whole, calorie restricted. Clearly, there were some lean times and survival issues, but when we evaluate what they ate and how they ate, their overall calorie intake was actually greater than ours today, but far more nutritionally dense, per volume of food. Simply put, they pretty much made a career out of finding food and eating it. Since our genetics haven’t changed much at all since then, this would seem to make the most sense. I highly doubt our ancestors willingly practiced calorie restriction, although I admit, I was not around 50,000 years ago, so I say what I say with that caveat.
Third, the most calorie restricted (and protein restricted) populations, on the planet, are generally the unhealthiest. The largest example of this is our elderly. It is a little unfair to lump Western elderly into this group, I realize, since they are the victims of Western diets. Protein calorie supplementation, in this group, generally improve their health and longevity, albeit not by much, since the “cat is probably out of the bag” at that point.
Fourth, much has been made about higher primates and calorie restriction, citing chimps that are calorie restricted live longer. If you use percentages, it is impressive, less so if you look at absolute longevity in years. And if you look at the two most famous examples “Canto” and “Owen”, for restricted and unrestricted ( I think the clips are still somewhere on youtube) you will see the behavioral differences between calorie restricted and non-calorie restricted higher primates and you will clearly not want to be the restricted one!
Calorie restriction in mice, extends the absolute longevity (the oldest mice are restricted), but does not change mean (average total) longevity.
Next, while there are clear cut genetic similarities between us and higher apes, there are still differences. One of them is the tiny matter of epigenetics, which will eventually prove to be central to all of our research.
I could go on, but here is the most important point for me anyway. CR (calorie restriction) has been intimately linked to the sirtuin pathway. This pathway is linked to p 53 and PPar gamma in humans. I have called these, the cellular gatekeepers. Ultimately, they seem to be under the control of their interactions with telomeres (as we recently found viz mitochondria-telomere length and function seems to control mitochondrial health and biogenesis, not vice versa). I think, whatever benefits on aging CR may have, will be far outweighed by focusing on telomere health. And finally, the effects of cellular regeneration and somatic (body) repair of calorie restriction are, at best, all over the place. Not so with telomerase activation. When the CR society does a mouse (or better yet a human study), that shows the kinds of AGE REVERSAL that DePinho and earlier researchers showed with mice, I will stand up and take notice. Until then, I personally practice a Paleo diet, which to a large extent, mimics the nutritionally dense, but relatively low calorie per unit of food patterns that fit our genetics.
Eventually, we may have a functional calorie mimetic (pterostilbene/resveratrol are not going to be the answer!).
My final point for today on this is CR may actually work (or not), but it will have no more success in an obese population, that loves to eat and we are far from understanding how to mimic CR at levels of the cell, in humans.
All of the above and much more, I have written and said/written, have made me unpopular with the CR people. I am open, to learn more, if I am missing something! I should end by saying that, NO DIET plan has been studied, with regards to human longevity and, given the difficulties involved, probably never will be, in a classic basic research fashion.