Want to live a long time? Who doesn’t? Quite a number of smart people have staked their hopes for long life on restricting their calorie intake. It’s an idea that rests on a not inconsiderable body of evidence. But some new developments suggest it may be a questionable strategy.
The idea that a diet containing a very modest energy content (measured in Calories or Kilojoules) could dramatically prolong lifespan is based on one of the most replicated findings in all of biology.
As long ago as 1935, researchers reported that lab rats fed dramatically restricted diets lived up to twice as long as rats allowed unrestricted access to food. The lifespan extending effects of dietary restriction appear to come about by delaying the onset of ageing and slowing the cellular damage and onset of diseases like cancers that naturally occur with age.
Since then, similar results have been obtained in mice, Rhesus monkeys, zebra fish, vinegar flies (Drosophila melanogaster), the nematode worm (Caenorhybditis elegans) and even yeast. The fact that dietary restriction prolonged lifespan and slowed ageing in such a variety of organisms strongly suggested that the underlying mechanisms are shared by all animals and possibly even all eukaryotes – the large group of complex organisms that includes animals, plants and fungi.
It didn’t take long for people to spot a potential route to slowing ageing and putting off the inevitable. Roy Walford championed what he called CRON – Calorie Restriction with Optimal Nutrition – in Beyond The 120-Year Diet. He argued that cutting dietary energy while maintaining micronutrient intake would prolong normal lifespan to well over a century, reducing the incidence of the major diseases of aging. Continue reading A hunger to live longer