Metabolic responses to night-time eating: a randomised control trial in men with high fasting lipids

Participants are required to undertake 2 overnight assessments (midnight to 6am) at the Be Active Sleep eat Facility BASE) at Monash University, Notting Hill. Prior to the first assessment participants are screened to ensure they meet eligibility criteria, anthropometric measurements are taken (height, weight and body composition), blood pressure and if deemed eligible asked to keep a 7 day food diary, sleep diary and wear an activity monitor for the same 7 day period prior to the first assessment. Participants are also required to complete a Medical and lifestyle history questionnaire to assess eligibility, Pittsburg Sleep Quality Index (PSQ1) to assess sleep habits over the last month and Morningness-Eveningness Questionnaire (MEQ) to assess whether the participants circadian rhythm produces peak alertness in the morning, in the evening, or in between. At 1200h and 1800h on the assessment days, subjects will be required to consume control meals and snacks for lunch and dinner (2636kJ, 29.4% protein, 49% carbohydrate, 32% fat and 1,288kJ, 14% protein, 66% carbohydrates and 15% fat, respectively). All control meals and snacks are to be consumed within 15 minutes. Subjects will then refrain from eating or drinking anything else (except for water) until they come into the BASE Facility for the night-time assessment. Upon arrival at the BASE facility at 23:00 for the assessment visits anthropometric (height, weight and body composition) measurements and blood pressure are recorded. The researchers will also check verbally that the control meals/snacks were consumed. An intravenous canula will then be inserted by an experienced nurse or phlebotomist 45 minutes before the start of the trial. One baseline blood sample will be taken at baseline ( time 0 minutes), followed by provision of a healthy meal (low glycaemic index meal) at 00:00 hrs (midnight) which participants will be asked to consume within 15 minutes. The test meal is a homemade vegetarian pasta dish (2.7 MJ, with 47% energy from carbohydrate (8% total sugars), 40% energy from fat (7% saturates) and 11% energy from protein). Blood sampling will be collected at 15,30,45,60,90.120,180.240,300, and 360 minutes for glucose, triglycerides and insulin. At hourly intervals, participants are asked about their subjective appetite by completing VAS scales on hunger and fullness, are asked to select from a picture of a vending machine what food they most feel like at that particular time point and to complete a Karolinska sleep scale (KSS) which is a measure of situational sleepiness. Blood samples for RNA extraction are being collected at 0, 120 and 240 minutes. The washout period between overnight assessment 1 and assessment 2 is a minimum of 7 days.