Circadian Rhythms and Time-Restricted Eating in Healthy Aging and Longevity

Abstract

The circadian clock is a highly specialized biological oscillator that regulates rhythms of metabolic and endocrine pathways critical for the maintenance of homeodynamic state of the body. Circadian rhythms affect nearly all aspects of behavior and physiology such as cardiovascular activity, body temperature, sleep–wake cycle, endocrine regulation, hepatic metabolism, and gastro-intestinal tract physiology. With increasing age, these endogenous rhythms are however dampened, thereby compromising temporal coordination between circadian clock and physiology. Consuming food that is out of sync with these circadian rhythms results in metabolic desynchrony, potentially increasing the risk of chronic lifestyle diseases. Recent studies have provided evidence that age-associated decline in metabolic health can be slowed down by alignment of the daily eating time window (Time-restricted eating—TRE) with the circadian clock. TRE is a nutritional intervention in which food intake is restricted to a 4–12 h time period without compromising on diet quality and quantity. Several preclinical and clinical studies have reported that TRE improves glucose tolerance, cardiometabolic and gut health, increase metabolic flexibility, reduce body weight, blood pressure, and atherogenic lipids. Since the biological clock regulates energy metabolism involving metabolic proteins as the key underlying factors, therefore, it is important to understand the role of circadian regulation over metabolism for maintaining health. Several human pilot studies have reported this regulation as a novel therapeutic/interventional strategy. This chapter will review the available data of experimental animals and human studies on the impact of meal timings and circadian rhythms in promoting healthy aging and longevity.