By Barbara Berkeley
In the January article that detailed her weight regain, Oprah famously mentioned the doctor who suggested that she “embrace hunger .” This was not a suggestion to which Oprah took kindly, nor would most of us. Yet there are a group of people who do welcome the sensation of an empty stomach. These are the practitioners of CRON, or Caloric Restriction with Optimal Nutrition.
The CR movement is a fascinating one. It is made up of people who believe that they can attain superior health and longer life by eating less…a lot less.
In the “60 Minutes” segment I wrote about last week, part of the focus was trained on caloric restrictors. This is because the subject of the segment was life extension. Significant restriction of calories has been shown to prolong life and promote vigor in almost every species tested to date. Humans, however, have not yet been studied. The major question that remains is whether eating a lot fewer calories wil also cause humans to live longer. No one yet knows. In a very real way, CRON practitioners are doing this experiment on themselves.
Why should a life of semi-starvation extend lifespan? The possible answer lies in the SIRT gene. This gene seems to prolong longevity when it is activated and caloric restriction appears to activate it. (As I mentioned in my earlier post, the chemical compound Resveratrol may also cause activation.) But why should such an adaptation exist? Perhaps this mechanism was designed so that a species could slow down aging in order to get past a period when food was scarce. This would give the species a better chance of reproducing and passing along its DNA. Another possibility is that the act of eating and processing food has a destructive side. Free radicals, for example, are destructive electrons that are thrown off by the body which damage cells and tissues, a process called “oxidative stress.” Perhaps when eating is curtailed, the damage is less and aging proceeds more slowly. At the present time, the exact mechanisms are unknown.
One of interesting sidebars to the caloric restriction saga is the story of Dr. Roy Walford. Dr. Walford was one of the first people to try to extend life by eating less. He also was a member of the crew of the Biosphere, an experiment you may remember. The Biosphere was a totally enclosed environment which grew its own food and recycled its air and water. A number of problems arose during the time he spent inside the Biosphere. Later on, however, Dr. Walford became a devoted practitioner of caloric restriction. Along with his daughter, he wrote a number of books about his belief in CRON. Unfortunately, Dr. Walford did not achieve the extended life he hoped for. He developed ALS (Lou Gehrig’s Disease) and died at age 79. He is said to have believed that the Biosphere experience, and not his diet, caused his illness. There is no way to know.
Animals such as monkeys and mice who are fed very limited calories are described as more youthful and vigorous then their well-fed peers. They have shinier coats and appear to be more energetic. You can make your own judgement about the human CR practitioners shown on “60 Minutes.” In my view, they did not look to be youthful, energetic or even particularly well. For a look at younger CRonies (as they call themselves), you can look at the CR website. These people look quite a bit healthier.
The question of what constitutes the optimal lifestyle remains unanswered. I wonder what you believe it to be? One thing is certain, there is not enough scientific evidence to provide any definite answer. As a result, optimal lifestyle practices remain a matter of opinion. Despite the built-in uncertainty, people who practice select lifestyles are often adamant about them and believe vehemently that their choice is best.
Early studies of CR practitioners reveal that their blood pressure, cholesterol, sugars and other health markers benefit from their lifestyle. But is it necessary for any of us to go this far for health? There is no question that those of us who maintain lowered levels of visceral fat and who eat diets that are closer to our original diet (vegetarian, Primarian, Mediterranean and other similar diets) have similar health benefits. Perhaps our goal should be healthy life, rather than extended life.
