RT Journal Article SR Electronic T1 Intermittent fasting: eating by the clock for health and exercise performance JF BMJ Open Sport & Exercise Medicine JO BMJ OPEN SP EX MED FD BMJ Publishing Group Ltd SP e001206 DO 10.1136/bmjsem-2021-001206 VO 8 IS 1 A1 Mandal, Sumona A1 Simmons, Niall A1 Awan, Sidra A1 Chamari, Karim A1 Ahmed, Irfan YR 2022 UL http://bmjopensem.bmj.com/content/8/1/e001206.abstract AB Intermittent fasting (IF) is an increasingly popular dietary practice, and its implementation is found throughout human civilisation in various cultural, spiritual and religious traditions. Emerging evidence has shown that the health benefits of IF stretch beyond calorie restriction and weight loss. These benefits include metabolic shifts in energy production, the optimisation of peripheral circadian clocks, and overall improvement in physiological markers of metabolic health. IF has been proposed to reduce systemic inflammation and have a role in the prevention and treatment of chronic disease. For the athlete, IF protocols offer a potential new frontier for maintaining performance in the fasted state. They may allow athletes to optimise training adaptions, while respecting individual cultural, religious, and/or spiritual preferences to fast and exercise. Below, we discuss the physiological impact of fasted exercise while highlighting areas for future work to improve our understanding and implementation of the practice for the benefit of both the active general community and sporting populations.