It’s as close to a genuine fountain of youth as you can get.
And yet it’s not new. It was first put forward as a way of extending life in the 16th century, and was extolled by Benjamin Franklin two centuries after that.
In the 1930s, scientists showed that, using this simple secret, they could extend the maximum lifespan of rodents by a whopping 40%. Even cautious scientists are willing to admit it works, not just in animals but in humans too.
The formula couldn’t be more simple. As Ben Franklin put it, “To lengthen thy life, lessen thy meals.”
Calorie Restriction For Life Extension
After the first experiments were carried out 80 years ago, scientists repeated them in many life-forms such as yeasts, fruit flies, spiders, worms, mice, rats, fish, snakes and dogs.
A 2009 study by the University of Wisconsin-Madison (UWM) confirmed that calorie restriction worked in monkeys, allowing them to live three years longer than usual, from age 26 to 29, the equivalent of about nine years in humans.
Calorie restriction seems to be successful in extending biological life in every life-form tested. It also benefits overall health. Those who practice it have a lower incidence of disease.
However, in 2012 a study from the National Institute of Aging (NIA) put a wrench in the works. The researchers found, in contrast to all other studies, that while it improved the health of rhesus monkeys, it didn’t extend their life.
This led to a collaboration between the NIA and UWM to find out why their results conflicted.
It Does Work After All
After reviewing many years’ work, and data from several hundred monkeys, the two research teams came to the conclusion that eating less does extend the life of these primates.
The discrepancies between their findings were the result of a number of factors. These concerned the composition of the diet, feeding times, differences in origin, age, sex, bodyweight and genetics of the monkeys.
A key finding was that eating less does not benefit younger animals. Calorie restriction (CR) needs, at least among primates, to be started in the adult and senior years. (And in case you weren’t paying attention in high school biology, we humans are primates.)
According to the researchers, “Data from both study locations suggest that the CR paradigm is effective in delaying the effects of aging in nonhuman primates but that the age of onset is an important factor in determining the extent to which beneficial effects of CR might be induced.
“CR mechanisms are likely translatable to human health.”
Calorie Restriction in Humans
While over a thousand experiments since the 1930s confirm both improved well-being and life-span in many species, the length of life lived by humans makes it virtually impossible to carry out life extension studies.
But a number of shorter studies have been conducted that look at biological markers of health. In these studies, calorie intake is usually reduced by about a quarter for a period of one or two years.
Findings include better heart function, reduced risk factors for cardiovascular disease, diabetes and certain cancers, lower markers for inflammation, and reduction in DNA damage.
Beneficial reductions were also found in two accepted biomarkers of longevity – body temperature and fasting insulin.
Another important finding was an increase in mitochondria (energy) production. The loss or dysfunction of cellular mitochondria is highly negative for both health and lifespan.
If calorie restriction is taken too far it can have negative effects, including muscle wasting, anemia, water retention and neurological deficits. These were seen when calories were restricted by 45% for six months.
People in their 50s eating a diet with a 25% calorie reduction, and not taking any exercise, saw losses of bone mineral density in the hip, spine and thigh as well as decreases in muscle mass and aerobic capacity.
People who follow the CR diet – also known as the high/low or longevity diet – aim for about 1500 calories a day for women and 1800 calories a day for men, with most of the food intake consisting of highly nutritious foods. For a “normal” diet the usual calorie recommendations are 2,000 for women and 2,500 for men.
The concept of eating less is simple, but that doesn’t mean it’s easy. It takes a lot of determination. No one likes to feel hungry for even a few days, never mind making it a lifelong practice. Even in human studies that reduce calories by only 16%, compliance is often poor.
If you do choose to give it a try, please make sure you do it under the supervision of your doctor or other knowledgeable health professional.