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 <8 h day^-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 and older adults, including trials with a longer treatment duration.