Metabolic Slowing and Reduced Oxidative Damage with Sustained Caloric Restriction Support the Rate of Living and Oxidative Damage Theories of Aging.
Level 2 - randomized trial
Individual randomized controlled trial
PubMed 29576535 · doi:10.1016/j.cmet.2018.02.019
What was done
Fifty-three non-obese adults were assigned to a calorie restriction diet (n = 34) or a control diet (n = 19) over 2 years. Investigators measured 24-hour and sleep energy expenditure, thyroid axis activity, and reactive oxygen species production via F2-isoprostane.
What was found
The calorie restriction group achieved approximately 15% calorie restriction over 2 years, resulting in an average weight loss of 8.7 kg compared to an average gain of 1.8 kg in controls. In the calorie restriction group, 24-hour and sleep energy expenditure was approximately 80 to 120 kcal/day lower than predicted based on weight loss alone. This metabolic adaptation was accompanied by significant reductions in thyroid axis activity and F2-isoprostane production.
Why it matters
This study provides randomized human evidence that prolonged caloric restriction induces persistent metabolic slowing alongside decreased oxidative damage. This directly supports the rate of living and oxidative damage theories of aging in humans.
Limits
The sample size is small (53 participants across two arms). The cohort consisted exclusively of healthy, non-obese adults, limiting generalizability to older or clinical populations. The study evaluated surrogate biomarkers of aging and metabolism rather than long-term clinical endpoints or lifespan.
Cited by
- supports Caloric restriction and rapid weight loss trigger a reduction in thyroid function and metabolic rate.