Benefits of Time-Restricted Eating

Time-restricted eating remodels the circadian rhythm to forestall the dangers of metabolic diseases like diabetes.

Circadian rhythms influence cellular processes and endocrine factors, creating optimum periods for sleep, activity, and nutrient intake within a 24-hour day. When such activities occur within the ideal circadian windows, they reinforce the circadian rhythm, thus optimizing organ functions and well-being. Conversely, disruption of circadian rhythms is associated with risks for infectious diseases, metabolic diseases, and other non-infectious diseases. Chaix et al. stated that time-restricted eating in alignment with a favorable circadian window could benefit multiple organ systems and improve health outcomes. Time-restricted eating is a method that limits food intake to a certain number of hours each day, a type of intermittent fasting.

The circadian clock is present in most tissues and cells. Therefore, disruption to the circadian rhythm can affect the functions of many organs and cells. For example, in the animal experiments, daytime access to food changes the circadian clock components in the liver. On the other hand, the liver plays a vital role in glucose, fat, and cholesterol metabolism. Therefore, dysmetabolism of these pathways can result in many metabolic diseases, including obesity and diabetes.

Time-restricted eating in animal studies showed that a restricted feeding window of 8 to 12 hours could provide health benefits even in the absence of calorie reduction. Manoogian et al. believed that time-restricted eating provides a more extended period of daily fast, which has effects on multiple pathways in different organs and on gut microbiome composition. Also, time-restricted eating may alter the liver’s biological rhythm and clock components through the influence of the critical regulators of gluconeogenesis and insulin signaling. Time-restricted eating can also increase lipolysis and beta-oxidation, resulting in the overall decrease of free fatty acid in the liver, consequently reducing inflammation associated with many metabolic diseases.

Several studies reported that time-restricted eating could improve glucose tolerance in patients with prediabetes. Evening and late-night meals are well-known causes for higher postprandial glucose. The mechanism is thought to be due to the circadian rhythm of insulin release in the morning (higher in the first half of the day) and melatonin release at night (can antagonize insulin release). Some other benefits of time-restricted eating include improved gut health and a longer lifespan. The gut microbiome varies throughout the day due to the daily rhythm of ingestion, secretion, digestion, absorption, and excretion. Disruption of the daily rhythm in the gut due to unscheduled eating windows can alter the gut’s chemistry and, ultimately, the microbiome. Ulgherait et al. studied the time-restricted eating (feeding) model in animals and found that time-restricted eating could increase lifespan by 18% in females and 13% in males. 

However, eating pattern (time of day, frequency, variation) is crucial in time-restricted eating. The eating window is determined as the 95% interval of all eating occasions over 7 to 14 days or more. Therefore, eating time changes can reset the circadian clock, affecting the endocrine system and the calculated eating window. Therefore, a consistent duration of eating windows is also essential to achieve the benefits of time-restricted eating.

Data from multiple studies showed that an eating window of 8 to 10 hours provides significant metabolic benefits and accommodates participants’ busy schedules for good compliance. Therefore, several clinical trials are undertaken to assess the benefit of time-restricted eating in different study populations (prediabetes, diabetes, metabolic syndrome). The results of these trials hopefully will further consolidate the benefits of time-restricted eating.

Practice Pearls:

• Eating meals at a consistent time, for example, following a time-restricted eating model with consistent eating windows of 8 to 12 hours, may lead to a lower risk of diabetes and heart diseases.
• Change in eating time, for example, breakfast time, can reset the circadian clock.
• Consistency of the eating times is vital and ought to be consolidated into ascertaining the eating window.

Manoogian, Emily N et al. “Time-restricted eating for the prevention and management of metabolic diseases.” Endocrine reviews. 22 Sep. 2021.

Chaix, Amandine et al. “Time-Restricted Eating to Prevent and Manage Chronic Metabolic Diseases.” Annual review of nutrition vol. 39 (2019): 291-315.

Ulgherait, Matt et al. “Circadian autophagy drive iTRF-mediated longevity.” Nature. 29 Sep. 2021,

Ding Nguyen, PharmD Candidate, University of South Florida Taneja College of Pharmacy