Researchers have long wondered whether calorie restriction is the key to longevity - and have now published new research which may answer their questions.
As part of an ongoing research project, started over a decade ago at the Pennington Biomedical Research Centre in Baton Rouge, Louisiana, researchers set out to uncover how calorie restriction could keep humans free from age-related diseases.
The Comprehensive Assessment of Long-Term Effects of Reducing Intake of Energy, or Calerie, relied on volunteers who willingly submitted to two years of reduced caloric intake, up to 25 per cent, as well as weekly tests of blood, bone scans, and body temperature.
In addition, the Pennington participants were required to spend 24 hours in sealed metabolic rooms where their every breath would be measured so scientists could decipher how their bodies burned calories and whether these calories came from fat, protein or carbohydrates.
The results of these experiments have recently been published in the journal "Cell Metabolism" - and cutting calories does lower the metabolism, by about ten per cent it turns out.
According to the authors of the study, this is due to altered biological processes - which reduce the amount of oxygen your body needs to function and perform activities.
“Restricting calories can slow your basal metabolic rate—the energy you need to sustain all normal daily functions,” says endocrinologist and lead author Leanne Redman.
And when your body uses less oxygen, it produces fewer by-products of metabolism - such things like free radicals which can damage DNA and other cellular machinery.
Although limited, the researchers believe that the study supports the “rate of living” theory - which suggests the slower an organism’s metabolism, the longer it will live.
However, other researchers aren’t as convinced - Luigi Fontana, an internist who led the Washington University trial, said: “You can have a low resting metabolic rate because you’re dying of starvation. Does that make it a biomarker of longevity? No. You can be calorie restricted by eating half a hamburger and a few fries each day but will you live longer? No, you will die of malnutrition.”
So while a diet of healthy caloric consumption is conducive to health, the effects of a restricted one may not be.
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