So you want to live a long life, or at least age gracefully?
Bill Gifford has provided a well-researched and engrossing account of the quest for longevity. In his new book, Spring Chicken, Gifford critically examines the claims of scientists, enthusiasts and hucksters in their attempts to extend life using hormone replacement therapy, telomerase, supplements, drugs, exercise, caloric restriction, intermittent fasting and other practices. Along the way, he visits with a 108-year old investment advisor and a 76-year old female sprinter who can run a 6:58 mile, and he takes a close look at mice, monkeys and microbes that live much longer than species norms.
I found the book hard to put down. That’s not merely because Bill’s hilarious account of my wintry swim with him in the Pacific Ocean appears in Chapter 12–as a bracing illustration of how hormesis builds stress tolerance. I was captivated by reading of his up-close encounters with a diverse set of gerontologists, centenarians and odd, long-lived creatures such as the naked mole rat. Most interesting of all was his meticulous detective work in probing the major competing theories of aging, leading to some unconventional conclusions about what may or may not actually help prolong life and healthspan.
One of the primary topics covered on this blog is intermittent fasting (IF). Many approach IF as a diet or weight loss method. I know from research, personal experience and conversations with others that IF can indeed be an effective way to drop unwanted pounds. However, viewing IF as merely a new way to diet entirely misses what I believe is the most important reason to pursue it: the activation of hormetic processes that foster improved health, keep degenerative diseases at bay, and hold out the promise of a longer, more vibrant life. These benefits are a known consequence of calorie restriction, but intermittent fasting offers a more comfortable and versatile way to reap the benefits of calorie restriction without the sense of deprivation, the loss of lean body mass, and the metabolic risks that have been associated with simple calorie restriction.
It is because I’ve found intermittent fasting to be an attractive practice, both scientifically and personally, that I was so excited to be invited to give a lecture on IF at The 3rd Door, an innovative health and fitness studio, cafe and social center in downtown Palo Alto. The fitness director at The Third Door, Johnny Nguyen, is himself an advocate and practitoner of IF, which he blogs about with great flair and common sense at The Lean Saloon. The talk gave me an opportunity to reframe intermittent fasting in the terms of the philosophy of Hormetism, or applied hormesis that I write about on this blog. I believe that the framework of hormesis helps to make sense of why IF works, and why it is so much more than a diet.
What follows is a video of my talk on the benefits of intermittent fasting, presented on May 18, 2011 at The 3rd Door. I would like to thank Dianne Giancarlo and Johnny Nguyen for inviting me to speak, Vaciliki Papademetriou for technical assistance, Francesca Freedman for introducing me to The Third Door, Tom Merson for the still photos and Ken Becker for the masterful video production.
Posted 23 May 2010 — by Todd
One of the first scientifically rigorous demonstrations of the benefits of hormesis was a 1934 study of calorie restriction (often abbreviated “CR”) in laboratory rats, conducted by Mary Crowell and Clive McCay at Cornell. They found that reducing the calories of rats by 30-50%, supplemented with adequate micro-nutrients, could almost double their lifespans. Later studies found continued lifetime extension with calorie restriction up to 65%. In addition, the rats remained energetic and youthful in appearance, with greatly reduced incidence, and delayed onset, of age-related diseases. This same phenomenon has been observed in a variety of other animals.
Studies on calorie restriction in primates or humans are as yet inconclusive. Controlled primate studies only started in the late 1980s and have yet to be completed, although the preliminary indications are very promising. And in humans it is more difficult to conduct controlled studies for both ethical and compliance reasons. An additional factor to consider is that animals raised post-weaning on calorie restricted diets typically have much smaller adult body sizes that animals not restricted in their eating. Because of the social and physical implications of this consequence, advocates of calorie restricted diets for humans advise that they be started only upon reaching adulthood.
Whether or not a restricted calorie diet extends the human lifespan, the evidence is becoming overwhelming that a nutritionally complete diet with reduced calories has the potential to greatly improve our health, particularly as we age. But is it practical and possible for humans to happily adhere to such a diet?