Effects of Early vs. Late Time-Restricted Eating on Cardiometabolic Health, Inflammation, and Sleep in Overweight and Obese Women: A Study Protocol for the ChronoFast Trial

Abstract

Background: Time-restricted eating is a promising dietary strategy for weight loss, glucose and lipid metabolism improvements, and overall well-being. However, human studies demonstrated contradictory results for the restriction of food intake to the beginning (early TRE, eTRE) or to the end of the day (late TRE, lTRE) suggesting that more carefully controlled studies are needed.Objective: The aim of the ChronoFast trial study is to determine whether eTRE or lTRE is a better dietary approach to improve cardiometabolic health upon minimized calorie deficits and nearly stable body weight.Methods: Here, we present the study protocol of the randomized cross-over ChronoFast clinical trial comparing effects of 2 week eTRE (8:00 to 16:00 h) and lTRE (13:00 to 21:00 h) on insulin sensitivity and other glycemic traits, blood lipids, inflammation, and sleep quality in 30 women with overweight or obesity and increased risk of type 2 diabetes. To ensure timely compliance and unchanged dietary composition, and to minimize possible calorie deficits, real-time monitoring of dietary intake and body weight using a smartphone application, and extensive nutritional counseling are performed. Continuous glucose monitoring, oral glucose tolerance test, 24 h activity tracking, questionnaires, and gene expression analysis in adipose tissue and blood monocytes will be used for assessment of study outcomes.Discussion: The trial will determine whether eTRE or lTRE is more effective to improve cardiometabolic health, elucidate underlying mechanisms, and contribute to the development of recommendations for medical practice and the wider population.Clinical Trial Registration:www.ClinicalTrials.gov, Identifier [NCT04351672]

The effects of early time restricted eating plus daily caloric restriction compared to daily caloric restriction alone on continuous glucose levels

“…Another area of interest is assessing how the timing of the eating window may affect glucose outcomes as there is both pre‐clinical and clinical evidence that the 24‐h circadian rhythm, which is synchronized with behavioral and environmental patterns, impacts nutrient utilization and storage 32 . Upcoming trials will further examine changes in continuous glucose and glycemic parameters in early versus late TRE interventions 66 . It is of particular importance to determine whether late TRE results in cardiometabolic improvements, given that many individuals attempting to follow TRE prefer a delayed eating window to better align with social eating occasions 67 .…”

“…There are fortunately several upcoming studies that will further assess the role of TRE in glucose metabolism with the use of CGM 64–66 . This is particularly important in populations with dysglycemia at baseline as most studies to date that have found favorable changes in continuous glucose profiles or glycemic parameters have been in individuals with baseline‐impaired glucose.…”

“…There are fortunately several upcoming studies that will further assess the role of TRE in glucose metabolism with the use of CGM. 64 , 65 , 66 This is particularly important in populations with dysglycemia at baseline as most studies to date that have found favorable changes in continuous glucose profiles or glycemic parameters have been in individuals with baseline‐impaired glucose. Another area of interest is assessing how the timing of the eating window may affect glucose outcomes as there is both pre‐clinical and clinical evidence that the 24‐h circadian rhythm, which is synchronized with behavioral and environmental patterns, impacts nutrient utilization and storage.…”

Meal Timing and Sleeping Energy Metabolism

“…The advocates of time-restricted eating have mainly focused on early time-restricted eating, resulting in a long interval between the last meal of the day and bedtime [ 54 ]. In a study of 90 healthy subjects, early time-restricted eating (6:00–15:00) was more effective than midday time-restricted eating (11:00–20:00) in improving insulin sensitivity.…”

Role of Circadian Clock on the Pathogenesis and Lifestyle Management in Non-Alcoholic Fatty Liver Disease

“…In contrast, TRF is a dietary approach defined as feeding within a period of ≤10 h and fasting for at least 14 h a day, where feeding is consolidated to the active period, aligning peripheral and central circadian rhythms [ 121 ]. This strategy could be divided into early (8 a.m. to 4 p.m.) and late (1 p.m. to 9 p.m.) [ 122 ]. When applied to human populations, TRF does not restrict the number of calories consumed or require a dietary profile of macronutrients, making it easier for patients to adopt.…”