Study: Calorie restriction helps only obese mice live longer
| Date: February 10, 2009 |
Does a calorie-restricted diet actually lengthen your life? Probably not unless you're already overweight, say scientists at the University of Southern California and North Texas Health Science Center.
The scientists studied two strains of JAX® Mice from The Jackson Laboratory to see whether subjecting them to a low-calorie diet prolonged their lifespan by lowering the rate of metabolism. The C57BL/6J mouse tends to gain weight throughout its lifetime, while the DBA/2J mouse stays lean.
The results, recently published in the Journal of Nutrition, showed that while calorie restriction did lower the metabolic rate in both strains, there was no effect on the lifespan of the DBA mice when compared to DBA mice that were allowed to eat as much as they wanted. The "dieting" C57BL mice did live longer than their free-feeding peers, but the researchers attributed that to the diet's returning the animals to a state of balance between their energy intake and energy expenditure.
In an article about the research published in ScienceDaily, the researchers commented further that for people who aren't overweight, using extreme calorie restriction as an anti-aging strategy "may be a pointless, frustrating and even dangerous exercise."
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Sohal et al.: Life Span Extension in Mice by Food Restriction Depends on an Energy Imbalance. Journal of Nutrition, Jan 2009; DOI: 10.3945/jn.108.100313
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