Metabolic Benefits of Calorie Restriction

Journal Watch. 2006;5(4) 


Dramatic calorie restriction is associated with increased lifespan in rats. Whether such a relation exists in humans, however, remains unknown. In this randomized trial, researchers evaluated the 6-month effects of calorie restriction on various biomarkers of longevity.

A total of 48 overweight but otherwise healthy adults (body-mass index, 25-30 kg/m2; mean age, 38) were assigned to one of four groups: weight maintenance, 25% calorie restriction, 12.5% calorie restriction plus exercise, or very low calorie intake (890 calories daily until weight was reduced by 15%). Subjects were weighed and received reinforcement weekly; at months 3 and 6, they underwent a range of metabolic tests as inpatients.

Of the 48 subjects enrolled, 46 completed the study, yielding a 96% retention rate that the authors attribute to the generous compensation provided. At 6 months, all three intervention groups showed significant weight loss (10%-14% of baseline weight), as well as significant reductions in fasting insulin levels and DNA damage. Both the 25% calorie-restriction group and the 12.5% calorie-restriction group showed significantly reduced core body temperature.


These improvements in biomarkers associated with longevity are, of course, only suggestive of an association between substantial calorie restriction and prolonged lifespan in humans. At the very least, the findings about the type of weight loss that can be achieved and maintained with intense behavioral intervention are impressive.

Thomas L. Schwenk, MD


Heilbronn LK et al. Effect of 6-month calorie restriction on biomarkers of longevity, metabolic adaptation, and oxidative stress in overweight individuals: A randomized controlled trial. JAMA 2006 Apr 5; 295:1539-48.

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