The CALERIE study of human calorie restriction was conducted some years ago. Participants aimed at 25% calorie restriction and achieved a ~12% reduction in calorie intake over a span of two years. A number of papers have been published on the positive results for participant heath, and researchers continue to produce new analyzes of the data. Here, researchers show that participants who conducted more physical activity while calorie restricted exhibit modestly better outcomes in a number of measures of health known to change favorably with the practice of calorie restriction.
It is unclear how physical activity energy expenditure (PAEE) influences calorie restriction (CR)-induced benefits in individuals without obesity. We examined associations between PAEE and healthspan markers and physical activity (PA) time during prolonged CR. In Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy (CALERIE) 2, participants without obesity were randomized to 25% CR or ad libitum control. This post-hoc analysis included baseline and 24-month data from participants in both groups who demonstrated CR. PAEE was calculated from total and resting energy expenditure. Outcomes included grip strength, aerobic capacity, glucose, insulin, blood lipids, and self-reported PA time.
Overall, 136 participants (97 females; average age 38.6 years; average BMI 25.3) who showed CR were analyzed. A smaller decrease in PAEE was associated with improved grip strength, homeostatic model assessment of insulin resistance, and high-density lipoprotein-cholesterol. PAEE change was not associated with aerobic capacity, low-density lipoprotein-cholesterol, triglycerides, glucose, or insulin. A smaller PAEE decline was associated with greater PA time. For some blood lipids, change in PAEE interacted with baseline BMI class: in participants who were overweight, higher PAEE was associated with lower triglyceride and triglyceride to high-density lipoprotein-cholesterol ratio, whereas in participants who were normal weight, it was related to increased total-cholesterol.
In conclusion, a smaller reduction in PAEE during CR was associated with small improvements in several healthspan markers and greater PA time. Maintaining PAEE during CR may enhance healthspan in individuals without obesity.
Link: https://doi.org/10.1186/s12966-025-01825-5
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