Westlake Precision Nutrition Study: Diet Challenges for Glucose Metabolism

This study aims for precision nutrition. Participants will be required to wear continuous glucose monitoring (CGM) for 14 days. The diet intervention will be carried out after wearing CGM on Day 1. Individual N-of-1 trial design will be employed during Day 2 to Day 7 to compare the difference of postprandial glucose response to white bread or plain oats. These two breakfasts will appear in alternating order every successive 2 days, and these successive 2 days will be defined as one set. There will be 3 sets during Day 2 to Day 7. Between lunch and dinner will be the wash out period for the remaining effect of the last breakfast intervention on blood glucose homeostasis. In this period, participants will be allowed to choose foods without restrictions, but dietary records are required. The period during Day 8 to Day 14 is defined as intermittent fasting (IF) period, and participants will experience moderate fasting on Day 9 and Day 13 with total energy intake restrained within 500-600 kcal. In these two fasting days, participants will be provided with daily three meals. Investigators will closely monitor participants' latent adverse response and compliance to ensure the intervention will be completed with adequate safety and high compliancy. Oral glucose tolerance test (OGTT) will be conducted in the morning of Day 8 and Day 14 to test the changes of glucose tolerance before and after one set of IF intervention. Electroencephalogram (EEG) and functional Magnetic Resonance Imaging (fMRI) scanning will be conducted as per standard procedure at baseline.