The effects of fasting compared to eating a meal or snack during simulated night shift on changes in metabolism associated with circadian misalignment: A protocol and methods paper

Abstract

Abstract Study Objectives This protocol paper outlines the methods that will be used to examine the impact of altering meal timing on metabolism, cognitive performance and mood during simulated night shift. Methods Participants (male and female) will be recruited according to a-priori selected sample size to com- plete a 7-day within and between subject’s laboratory protocol. Participants will be randomly assigned to one of three conditions: meal at night or snack at night or no meal at night. This protocol includes an 8h night- time baseline sleep, followed by 4 consecutive nights of simulated nightshift (7h day sleep; 10:00h-17:00h), and an 8h night-time sleep (return to dayshift). During simulated night shift, meals will be provided at ~06:30h, 09:30h, 14:10h and 19:00h (no eating at night); ~06:300h, 19:00h and 00:30h (meal at night); or ~06:30h, 14:10h, 19:00h and 00:30h (snack at night). Meal composition will be strictly controlled throughout the study (45-65% carbohydrates, 15-25% protein and 20-35% fat per day) with daily energy provided to meet individ- ual needs using the Harris Benedict equation (light/sedentary activity). The primary outcome measures are serum concentrations of blood glucose, insulin and free fatty acids area under curve (AUC) in response to oral glucose tolerance test. Mixed effect ANOVAs will be conducted. Conclusion This protocol paper describes a methodology to describe an innovative approach to reduce the metabolic disease burden associated with shift work.