A scoping review of intermittent fasting, chronobiology, and metabolism

Abstract

Abstract Chronobiology plays a crucial role in modulating many physiological systems in which there is nutritional synergism with meal timing. Given that intermitting fasting (IF) has grown as a flexible dietary method consisting of delayed or early eating windows, this scoping review addresses the effects of IF protocols on metabolism as they relate to clinical nutrition and the circadian system. While nocturnal habits are associated with circadian misalignments and impaired cardiometabolic profile – and nutritional physiology is better orchestrated during the day – most findings are based on animal experiments or human studies with observational designs or acute meal tests. Well-controlled randomized clinical trials employing IF protocols of delayed or early eating windows have sometimes demonstrated clinical benefits, such as improved glycemic and lipid profiles, as well as weight loss. However, IF does not appear to be more effective than traditional diets at the group level, and its effects largely depend on energy restriction. Thus, efforts must be made to identify patient biological rhythms, preferences, routines, and medical conditions before individual dietary prescription in clinical practice.