According to a new study, calorie restriction may modify risk factors for age-related diseases and indicators associated with longer life span. The results of this research were published in the Journal of Gerontology: Medical Sciences and supported by the National Institutes of Health (NIH).
In the Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy (CALERIE) study, 218 young and middle-aged healthy normal-weight and moderately overweight men and women were randomized to a reduced caloric intake diet of 25% below one’s regular intake or maintenance of one’s regular diet. The calorie restriction group was given weight targets of 15.5% weight loss in the first year and weight stability over the second year; weight loss was expected to be achieved by reducing calorie intake by 25% below one’s regular intake at baseline. The other participants maintained their regular baseline diets over the two-year study.
The calorie restriction group lost an average of 10% of their body weight in the first year and maintained this weight over the second year. The control group’s weight and calorie intake were stable over the study period. Although the weight loss by the calorie restriction group was the largest sustained weight loss reported in any dietary clinical trial of non-obese participants, the weight loss fell short of the target. The intervention arm only reached 12% caloric restriction instead of the trial’s 25% goal but did maintain calorie restriction over the entire two-year period.
Calorie restriction also significantly reduced several predictors of cardiovascular disease compared to the control group, such as decreasing average blood pressure by 4% and total cholesterol by 6% and increasing HDL-C levels. Calorie restriction led to a 47% reduction in levels of C-reactive protein and markedly decreased insulin resistance. Of particular interest is the observed reduction of T3 by more than 20%, as some studies have suggested that lower thyroid activity may be associated with longer life span.
Next steps include evaluating additional long-term benefits of calorie restriction, such as effects on predictors of health in old age compared to effects with exercise-induced weight loss.
For more information visit NIH.gov.