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）可改善心血管功能与多项健康寿命相关生理指标。但对于非肥胖老年人群而言，长期热量限制存在诸多现实局限：可能引发瘦体重与骨密度流失、受试者依从性差，还存在营养不良风险。限时进食（time-restricted feeding, TRF）无需减少每日热量摄入，仅需限制每日进食窗口，有望成为中老年人延长健康寿命的可行替代方案，但目前关于其在人体中的可行性与有效性的研究证据仍较为匮乏。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群体开展短期限时进食（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，并初步探索其改善心血管功能及其他健康寿命相关指标的潜在效果。结果显示，限时进食方案安全性良好、耐受性佳，受试者依从性极高且饥饿感有所降低，且未对瘦体重、骨密度或营养摄入产生不良影响。本研究的健康受试者队列中，短期限时进食未改善心血管功能，但受试者的功能（耐力）能力与葡萄糖耐量均得到小幅提升。本研究结果为开展针对中老年人限时进食的更大规模临床研究奠定了基础，包括干预周期更长的相关试验。