Short-term time-restricted feeding is safe and feasible in non-obese healthy midlife and older adults

Chronic calorie restriction (CR) improves cardiovascular function and several other physiological markers of healthspan. However, CR is impractical in non-obese older humans due to potential loss of lean mass and bone density, poor adherence and risk of malnutrition. Time-restricted feeding (TRF), which limits the daily feeding period without requiring a reduction in calorie intake, may be a promising alternative healthspan-extending strategy for midlife and older adults; however, there is limited evidence for its feasibility and efficacy in humans. We conducted a randomized, controlled pilot study to assess the safety, tolerability and overall feasibility of short-term TRF (eating <8h·d-1 for 6 weeks) without weight loss in healthy non-obese midlife and older adults, while gaining initial insight into potential efficacy for improving cardiovascular function and other indicators of healthspan. TRF was safe and well-tolerated, associated with excellent adherence and reduced hunger, and did not influence lean mass, bone density or nutrient intake. Cardiovascular function was not enhanced by short-term TRF in this healthy cohort, but functional (endurance) capacity and glucose tolerance were modestly improved. These results provide a foundation for conducting larger clinical studies of TRF in midlife/older adults, including trials with a longer treatment duration.长期热量限制（chronic calorie restriction, CR）可改善心血管功能及多项健康寿命相关生理指标。然而，对于非肥胖老年人群而言，长期热量限制并不现实，因其可能引发瘦体重与骨密度流失、依从性不佳及营养不良风险。限时进食（time-restricted feeding, TRF）通过限制每日进食时长且无需减少热量摄入，或可为中老年人群提供一种颇具前景的健康寿命延长替代策略；但目前关于其在人体中的可行性与有效性的相关证据仍较为有限。本研究开展了一项随机对照预试验，旨在评估健康非肥胖中老年人群采用短期限时进食（每日进食时长＜8小时，持续6周）且无体重减轻方案的安全性、耐受性与整体可行性，同时初步探索其在改善心血管功能及其他健康寿命指标方面的潜在有效性。结果显示，限时进食安全性良好且耐受性佳，依从性优异且可降低饥饿感，且未对瘦体重、骨密度或营养摄入产生影响。在本次健康受试者队列中，短期限时进食未改善心血管功能，但受试者的功能（耐力）能力与葡萄糖耐量得到了轻度提升。本研究结果为开展针对中老年人群的更大规模限时进食临床研究奠定了基础，其中可纳入更长干预时长的试验方案。