Time-restricted eating for improved metabolic health: aligning meals with circadian rhythms

Abstract

Background. Ancient man relied on their circadian clock, driven by natural light to regulate feeding behaviors. Modern eating habits and artificial light have disrupted our circadian rhythm which could lead to metabolic diseases. Certain appetite and satiation hormones have varying levels based on the circadian rhythm. Objective of the study. To Investigate the optimal daily eating window based on circadian rhythms for improved metabolic health and the influence of the suprachiasmatic nucleus (SCN) on hunger hormones. Material and methods. This article is based on information gathered from many publications and literature published since 2017 that are accessible on PubMed, PMC, Google Scholar and NCBI. Result. Eating habits like time restricted eating (TRE) and intermittent fasting with a feeding window of 6-10 hours (8am - 6pm) and a fasting period of 14-18 hours aligns with the circadian rhythm and has been shown to benefit weight loss and improve insulin sensitivity due to synchronization of peripheral hormone secretion with the SCN. TRE has also been shown to lower triglyceride and LDL cholesterol levels. It is recommended that food intake begins at 8am after the cortisol peak, signaling the beginning of the activity phase, and end at the ghrelin and insulin peak around 6pm. Ghrelin levels increase across the day while leptin has higher levels at night. Circadian misalignment alters these hormones and therefore eating behaviors which may lead to impaired glucose tolerance and increased fat accumulation. Conclusion. This study highlights the importance of circadian rhythm in regulating appetite hormones and metabolic health. By synchronizing mealtimes with hormonal fluctuations within an eating period, TRE promotes optimal metabolic function and prevents chronic metabolic disorders.