Calories or Time Restriction to Alter Biomarkers of Aging and Diabetes

Inclusion Criteria: * Overweight or obesity (BMI 25.1 - 44.9 kg/m2) * Elevated waist circumference (race specific), * Elevated fasting blood glucose (\>5.6 mmol/L). Exclusion Criteria: A personal history/diagnosis (self-reported) of: * diabetes (type 1 or 2) * major psychiatric disorders (schizophrenia, major depressive disorder, bipolar disorder, eating disorders) * gastrointestinal disorders/disease (including malabsorption) * haematological disorders (i.e. thalassemia, iron-deficiency anaemia) * insomnia * obstructive sleep apnea * night eating syndrome * diagnosis or treatment of cancer in the past 3 years (excluding non-melanoma skin cancer) * significant liver or kidney diseases that require ongoing medical care * previous or planned gastro-intestinal surgery (including bariatric surgery) * Congestive heart failure (NYHA stage 2 or above) * Previous myocardial infarction or significant cardiac event ≤ 6 months prior to screening * Previous cerebrovascular event ≤ 12 months prior to screening * Any autoimmune disease (i.e. rheumatoid arthritis) * Coeliac disease * Score less than 12 of the Australian Diabetes (AUSD) risk assessment tool * Do not eat for a 12 hour window each day for 5 or more days per week * Have extreme or restricted patterns of eating (i.e. following an intermittent fasting diet) or already engage in CR * Other dietary restrictions including vegans, gluten or nut allergies * Night shift-workers (\>3 shifts per month) * pregnant, planning a pregnanc…