More coverage of the 4th annual Calorie Restriction (CR) Society conference is up in various locations around the web, including some from local media outlets. There will be more from the CR blogosphere to come later, no doubt, once people have had a chance to return home and wind down. Some excerpts are below, but there's too much to quote effectively; you should go and read the sources.
Conference co-organizer Robert Krikorian said he thought attendees expected less from calorie restriction, at least in terms of life extension, than did attendees at the first conference, held in 2001.
Luigi Fontana gave an update on human CR studies in progress that show CR practicioners have extremely low markers for cancer and heart disease risk and noted one study in which raw foodists had markers in some (but not all) areas as good as CR practicioners suggests that protein restriction may be something to study.
Aubrey de Grey suggested that the CR effect is mostly absolute and will not effectively scale for long lived organisms due to famines lasting a similar amount of time for organisms regardless of lifespan, resulting in only two or three years' increase in life span for CR'd humans.
The amount of research is really very small, considering the potential value of CR. Funding is very hard to get. There is a lot of bias against longevity research.
The evidence from studies to date is pretty sketchy and inconclusive. You can interpret it many different ways. Several of the researchers there had a strong belief bias towards the hypothesis that they have invested considerable career resources in. I felt very agnostic compared to all of them. There was a lot of interesting debate.
To me there was a big gap between the "pathway" people and the old-style biologists. The "pathway" people were very systems-oriented and seemed comfortable with the complexity presented by the human body. They had ways to deal with it. The old-style people are just poking sticks at things to see what happens. Too, too slow. Too, too simple. However, two of the "non-pathway" people, Josh Mittledorf and Aubrey De Grey are pretty out of the box thinkers. They force people to re-examine their ideas. A very good thing.
Aging theorists (Aubrey De Grey, Josh Mitteldorf, Ed Masoro, Steve Austad) are not sure that CR will extend life in humans the way it does in other animals. It might - it might not. The animal evidence is complicated and somewhat contradictory. Traditional experiments on animals are somewhat "blunt instruments" - the results are so dependent on laboratory conditions and the animal's genetics. Evolutionary biology is so theoretical at this point, it can support many different conflicting hypotheses about human life extension.
I think the evidence strongly implies that CR will work in humans to extend life (disagreeing with Aubrey ). For it to have a short term effect - of only one season or two - as Aubrey De Grey suggested in his talk - he assumed that the CR effect would "turn off" after a year or two. Luigi's testing shows that it does not. His test results were remarkably consistent for people of many different ages and genetic backgrounds, on different diets, and on CR for different amounts of time. He claims that if you give him a blood test results for someone and he knows their age, he can say definitively whether they are on CR or not. There is no evidence that it turns off - even after a decade or more. And, the kind of gene expression changes in rats appear to be echoed in humans. The only question is whether there is something in humans that makes these changes ineffective in extending life.
"A large percentage of people enjoy the diet, but a lot of people would trade the diet for a pill," Calorie Restrictive Society president Brian M. Delaney said.
The society's philosophy - that slashing calories will lead to a longer, healthier life - has been supported by numerous scientific studies on rats and mice, which consistently show an extended lifespan when put on a diet of 30 to 50 percent fewer calories. A study sponsored by the National Institute on Aging published this week in The Journal of the American Medical Association also showed that reducing calories in 48 people for six months led to decreases in both body temperature and insulin levels, typically considered signs of longevity.
"A lot of the misery and decrepitude of old age is disease, conditions like Type II diabetes and cardiovascular disease," CR Society president Brian M. Delaney said. "A lot of people not on this diet at 58 absolutely would start getting Type II diabetes. We want to start promoting more research into how to implement the diet, or if an alternative can be created."
The evidence for calorie restriction as the best thing most of us could presently be doing for our long term health is overwhelming. CR is small potatoes in the grand scheme of what is possible through future medical science, however. This is even more reason to practice CR - it greatly increases your chances of living to see a future of working anti-aging medicine.
The debate over the degree of human healthy life extension provided by calorie restriction will no doubt continue into the era in which it doesn't matter anymore, unless a clever and widely accepted method of extrapolating the effects of CR on human longevity is developed first. The demonstrated, proven benefits to human health and resistance to age-related degeneration should be more than enough to convince you to give it a try, however.