People who cut their daily kilojoule intake by 25% or more may live longer than those who do not, a new study suggests.
Researchers from the Washington University School of Medicine in St. Louis found that significantly limiting kilojoules lowers core body temperature (the temperature at which all of the functions in the body can operate with maximum efficiency), which has been shown to prolong life.
The study, published recently in the journal Aging, compared the core body temperatures of 24 people in their mid-50s who practised kilojoule restriction for at least six years to 24 of their peers who ate a standard Western diet with higher kilojoule and fat intake. The core body temperatures of 24 endurance runners in the same age group were also measured to determine if simply being lean was enough to lower body temperature without kilojoule restriction.
"The people doing a kilojoule restriction diet had a lower average core body temperature by about 0.2 degrees Celsius, which sounds like a modest reduction but is statistically significant and similar to the reduction we have observed in long-lived, calorie-restricted mice," principal investigator Dr Luigi Fontana said in a news release from Washington University. "What is interesting about that is endurance athletes, who are the same age and are equally lean, don't have similar reductions in body temperature."
Although restricting kilojoules can double or even triple the life-span of simple organisms, the researchers admitted it is not yet clear how much longer kilojoule restriction might help humans live. The study authors noted that those who practise the strict diet hope to survive past 100 years.
Limit kilojoules and eat well to live longer
The researchers also pointed out that simply lowering body temperature isn't enough to increase life span. Fontana noted that how lower core body temperatures are achieved is important. "I don't think it ever will be possible to be overweight and smoking and drinking and then take a pill, or several pills, to lower body temperature and lengthen life span," he said.
"What may be possible, however, is to do mild kilojoule restriction, to eat a very good diet, get mild exercise and then take a drug of some kind that could provide benefits similar to those seen in severe kilojoule restriction," Fontana added.
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