Death is a New Invention 2
There's a surprisingly easy way to live for a longer period of time in a greater state of health - just eat less! (Note: this story is not recommended for consumption by current or aspiring supermodels)
Death is a fairly new invention. Even today, we really don't know why we get old, and then die! But there's a surprisingly easy way to live for a longer period of time, in a greater state of health and here's the simple secret - just eat less!
Sixty years ago, Clive M. McCay and his colleagues at Cornell University placed rats on a very low calorie diet. They were astonished to find that they could increase the maximum lifespan of their rats by one third - from three years to four years. They also found that these rats on the low-calorie diet stayed younger for longer, and had fewer of the diseases that their fellow rats on a standard diet got as they grew older.
Since then, various scientists have experimented with all kinds of creatures (spiders, water fleas, guppy fish, various parasites and so on), and have been able to increase both the average lifespan, and the maximum lifespan.
Now there's a big difference between increasing the average lifespan and the maximum lifespan.
Increasing the average lifespan just means stopping unnecessary and premature deaths - such as deaths from car accidents, infectious diseases which could be easily stopped by vaccination, heart disease, and so on.
And yet, that's what reducing the calories seems to do.
But increasing the maximum lifespan is a whole different kettle of fish. If you can increase the maximum lifespan of various members of a species, you're somehow fooling around with some basic aging process.
Now we know that this "reduced calorie-intake increased-lifespan thingie" works in quite a few animals, but we haven't fully tested it in the two-legged animals. That began only about 15 years ago, when two separate groups of scientists began testing rhesus monkeys.
It's early days yet, but already there are quite a few interesting changes. As you would expect, the monkeys that have been eating 30% fewer calories, weigh about 30% less, and have only 10% of their body weight as fat - instead of the normal 30%. What is interesting is that all of their measures of health, even a few years into the experiment, are those of much younger monkeys. So the skinny monkeys have lower blood pressure, lower blood glucose level, lower insulin level, much lower blood cholesterol, and so on.
We have not yet done the same experiment with humans. There's no point in looking at people that have been forced by poverty to live on very low calories, because usually their low calorie diets don't give them enough essential nutrients.
So if you want to increase your life expectancy, you can't begin this calorie restriction thing when you're a child. The age of 20, as a starting point, would probably give you the greatest extension of life, but it's never too late to start. And it also seems that you can't simply go cold turkey and suddenly reduce your calories by 30% - you need a gradual tapering off. And most importantly, with a low-calorie diet, you still need to have your essential nutrients. You would have to select your foods extremely carefully, and probably have to take vitamins as well.
And there would be side effects, besides being hungry a lot of the time. A woman whose weight is very low, might not ovulate, and so could not have babies. And this lack of ovulation could lead to increased osteoporosis. Indeed, Professor Stewart Truswell, of the Sydney University Human Nutrition Unit, said that while the current scientific studies were interesting, "it certainly wouldn't make me go and eat less than I normally eat."
On the other hand, most of us could certainly afford to lose a little weight, and if we did it in a gentle fashion there would be hardly any side effects at all, while it really is eating lots. Just remember, the outcome of life is inevitably death - and all we're really doing is putting off, for a little while, the inevitable....
Published 09 November 2001
© 2015 Karl S. Kruszelnicki Pty Ltd