Caloric restriction and time-restricted eating in older adults with overweight or obesity: The Health, Aging, and Later-Life Outcomes Pilot Study

BACKGROUND: In animal models, caloric restriction (CR) and time-restricted eating (TRE) extend lifespan and healthspan; however, the long-term benefits in humans are unknown. The goal of the Health, Aging and Later-Life Outcomes Pilot (HALLO-P) was to inform the design of a definitive trial to evaluate the long-term effects of CR and TRE in older adults with overweight or obesity. METHODS: HALLO-P randomized 90 older (≥60 years) adults with obesity or overweight to one of three 9-month interventions: (1) 20% CR delivered in-person; (2) 20% CR delivered remotely (RCR); and (3) 8-hour TRE with ad libitum caloric intake. The degree of sustained CR (by doubly labeled water), the sustainability of TRE, participant retention, and changes in body mass and composition, physical performance, and cardiometabolic risk factors were examined. RESULTS: Participants had a mean (SD) age of 67.2 (4.9) years and BMI of 31.7 (2.9) kg/m2; 62% were female and 83% White. Participant retention was 92%. The mean (SD) percent CR was 4.5% (11.0) in CR and 6.0% (10.3) in RCR. TRE participants reported eating within an 8.5-hour window a median of 84% of days. Mean change in body mass was -4.4, -6.7, and -1.0 kg in CR, RCR, and TRE, respectively. CR and RCR lost fat and lean soft tissue. Chair stand and 400-m walk times improved in RCR and TRE, and there were improvements in glucose and cholesterol levels in all 3 groups. CONCLUSIONS: HALLO-P showed that the CR and TRE interventions were feasible and associated with improvements in health status over 9 months despite not achieving the target CR.