Time-restricted eating and age-related muscle loss

regular periods of fasting have been explored for improving health and combating disease [1, 2]. While numerous rodent studies have demonstrated potential benefits of fasting for prevention or treatment of agerelated diseases, including diabetes, cardiovascular disease, neurological disorders, and cancer, more limited evidence is available in humans [1]. Although preliminary findings indicate that the incorporation of fasting may hold promise for some of the aforementioned conditions, whether fasting would be beneficial, inconsequential, or deleterious is less clear for others. For example, sarcopenia the loss of skeletal muscle mass and function associated with old age is a notable concern of the aging population. The functional limitations and physical disability attendant to sarcopenia contribute to reduced quality of life and mortality [3]. The primary anabolic stimuli that can help preserve or increase skeletal muscle mass with aging are exercise and protein intake [4]. Based on investigations of acute muscle protein synthesis responses, it has been recommended to evenly distribute protein intake over the course of waking hours and to consume per-meal protein doses that maximize muscle protein synthetic responses (~0.4 g/kg/meal, with a daily intake of ~1.2 g/kg/d) [4]. The even distribution of protein throughout the day may be viewed as generally at odds with programs incorporating daily fasting periods longer than an overnight fast, such as time-restricted eating (TRE; also known as time-restricted feeding) in which all calories are consumed within a truncated period of time each day. However, some TRE programs would be amenable to the general recommendation of consuming protein boluses of ≥ 0.4 g/kg/meal for ≥2 meals per day. For example, the commonly employed 8-hour eating window could allow for 2 to 3 meals with protein doses ≥ 0.4 g/kg/meal and a daily intake of ≥ 1.2 g/kg, with a relatively minor consolidation of eating occasions relative to longer eating windows of ≥ 10 hours. Additionally, as it has been noted that the elderly experience a diminished anabolic response to a given quantity of protein as compared to young adults [4], there is a possibility that consolidating more numerous eating occasions into several larger boluses could actually aid in meeting per-meal protein intakes necessary for maximal stimulation of muscle protein synEditorial