Time RestrIcted Feeding For Improving Diabetes Risk (TRIFFID)

Following a 2 week baseline monitoring phase (food intake by smartphone APP, activity by accelerometer, glucose by continuous glucose monitor), participants will attend the metabolic clinic for testing (visit 0). Body weight, body composition (by DEXA), and blood pressure will be assessed. Blood and adipose tissue samples will be collected over 24-hour period for assessment of glucose, insulin, glucoregulatory hormones, blood lipids and adipose tissue transcriptome. Glucose and insulin responses to a standardised breakfast will be measured. All food will be provided for 3 days prior to the metabolic visit. Following visit 0, participants will be instructed to eat only within a 10-hour time frame each day for 8 weeks. Participants may self-select the precise window that best suits their lifestyles, however any food and drink must be consumed at least 3 hours prior to their usual bedtime. 24-hour glucose profiles, activity and food intake will be measured again at week 6-8. At the end of the 8 weeks, participants will return for a follow-up metabolic visit, identical to that at visit 0, except foods are provided with the 10h time frame.

Inclusion criteria

• Waist circumference ≥94 cm
• Weight-stable (< 5 % fluctuation in their body weight for past 6-months at study entry)

Exclusion criteria

• Personal history and/or diagnosis of: diabetes, cancer, major psychiatric disorders, liver disease, gastro-intestinal surgery or disease (including malabsorption), eating disorders, anaemia, insomnia, cardiovascular disease deemed unstable by the study physician.
• use of prescribed or non-prescribed medications which may affect energy metabolism, gastrointestinal function, body weight or appetite, sleep (e.g: domperidone and cisapride, anticholinergic drugs (e.g.: atropine), metoclopramide, orlistat, thyroid medications, diuretics, glucocorticoids, sex steroids, metformin, dipeptidyl peptidase-IV inhibitors, melatonin)
• recent weight change in past 3 months (> 5% current body weight)
• individuals who regularly perform high intensity exercise (>2 week)
• current intake of > 140g alcohol/week
• current smokers of cigarettes/cigars/marijuana/e-cigarettes/vaporisers
• current intake of any illicit substance
• unable to comprehend study protocol
• currently performing shift work
• has undertaken, or is planning to undertake, trans meridian travel during the study period, or the preceding 60 days
• do not own a smartphone
• eats for less than a 12-hour period per day