Purpose: Calorie restriction (CR) improves health span and delays age-related diseases in many species. The multicenter Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy (CALERIE) study was the first randomized controlled trial of CR in nonobese humans. The aim of this investigation was to determine the effects of CR on V˙O2max and muscle strength in the CALERIE trial.
Methods: Healthy, normal-weight, and mildly overweight women and men (n = 218, mean ± SE age = 37.9 ± 0.5 yr) were randomized to 25% CR or an ad libitum (AL) control condition in a 2:1 allocation (143 CR, 75 AL). V˙O2max was determined with an incremental treadmill test; the strength of the knee flexors and extensors was assessed by dynamometry at baseline, 1 yr, and 2 yr.
Results: The CR group achieved an average 11.9% ± 0.7% CR during the 2-yr intervention. Body weight decreased in CR (−7.7 ± 0.4 kg), but not AL (+0.2 ± 0.5 kg). Absolute V˙O2max (L·min−1) decreased at 1 and 2 yr with CR, whereas V˙O2max expressed relative to body mass increased at both time points (1 yr: +2.2 ± 0.4; 2 yr: +1.9 ± 0.5 mL·kg−1·min−1) and relative to AL. The CR group increased their treadmill test time and workload at 1 and 2 yr. Strength results in CR were similar, with decreases in absolute flexor and extensor strength, but increases when expressed relative to body mass. No changes were observed for V˙O2max expressed relative to lean body mass or leg lean mass.
Conclusions: Two years of modest CR without a structured exercise component did not appear to compromise aerobic capacity in healthy nonobese adults. The clinical implications of the observed changes in V˙O2max and muscle strength will be important to explore in future studies.
1Program in Physical Therapy, Washington University School of Medicine, St. Louis, MO; 2Department of Medicine, Washington University School of Medicine, St. Louis, MO; 3Duke Clinical Research Institute, Durham, NC; 4Rho Federal Systems, Chapel Hill, NC; 5Michael E DeBakey VA Medical Center, Baylor College of Medicine, Houston, TX; 6Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA; 7Department of Clinical and Experimental Sciences, Brescia University Medical School, Brescia, Italy; 8Healthy Aging Center, CEINGE Biotecnologie Avanzate, Napoli, Italy; 9Pennington Biomedical Research Center, Baton Rouge, LA; and 10Department of Medicine and Duke Molecular Physiology Institute, Duke University School of Medicine, Durham, NC
Address for correspondence: Susan B. Racette, Ph.D., Washington University School of Medicine, Campus Box 8502, 4444 Forest Park Ave., St. Louis, MO 63108; E-mail: firstname.lastname@example.org.
Submitted for publication December 2016.
Accepted for publication June 2017.
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