The Panacea of Human Aging

Calorie Restriction Versus Exercise

Nicholas T. Broskey; Kara L. Marlatt; Jasper Most; Melissa L. Erickson; Brian A. Irving; Leanne M. Redman


Exerc Sport Sci Rev. 2019;47(3):169-175. 

In This Article

CR Combined With Exercise

Well-controlled studies from our group and others have compared exercise versus CR on attenuating factors associated with primary and secondary aging. The 12-month CALERIE-1 trial in overweight adults found that both exercise and CR resulted in similar reductions in energy expenditure,[48] as well as reductions in markers of DNA and RNA damage.[49] Exercise with CR compared with CR alone resulted in no increased reductions in body weight and adiposity, and improvements in insulin sensitivity and glucose tolerance were comparable.[48] This work was replicated by our team over a 6-month period with the added benefit of improvements in aerobic capacity (i.e., V̇O2max) with exercise.[28] In our CALERIE-1 and 2 cohorts of overweight adults (25–50 yr), we reported that a combination of CR and exercise showed similar improvements in cardiovascular risk factors including blood pressure, lipidemia, and heart rate variability compared with CR alone.[24,25] These benefits may be more pronounced in aging populations given that combining exercise and CR has better outcomes than CR alone.

In older adults, CR and exercise together seem to have an additive effect on glucose homeostasis compared with CR alone (45–65 yr), even after matching for energy deficit.[50] Indeed, CR with the inclusion of exercise has been shown to preserve not only fat-free mass (i.e., lean muscle mass, bone density), but also enhance aerobic capacity and increase strength. Therefore, incorporating both CR and exercise might be most relevant in elderly populations who are at risk for frailty and falls.

It must be acknowledged that there are some shared, and unique, limitations to both CR and exercise; thus, determining the most suitable approach for an individual requires an understanding of the benefits and caveats to both. The outcomes of either approach equally depend on individual adherence. In addition, the risk of weight regain exists in response to both interventions. Interestingly, the unique drawbacks of either approach may be partially offset by the other. For example, a limitation specific to CR is the reduction in fat-free mass, skeletal muscle strength, and bone mineral density. In contrast, exercise stimulates muscle protein synthesis and may counteract declines in skeletal muscle mass, strength, and bone mineral density. A limitation specific to exercise is the increase in oxidative stress, which may negatively influence health in high doses. In contrast, CR reduces oxidative stress markers. Weighing the drawbacks of either approach, concurrent implementation of CR and exercise in a complementary and sustainable fashion may yield the greatest benefit.