Westlake Precision Nutrition Study
Condition: Healthy; Overweight and Obesity
MeSH terms: Overweight
Study type: Interventional

Summary: 
      This is a dietary intervention study, which aims to explore different diet challenges for
      glucose metabolism, including carbohydrates and intermittent fasting (IF) dietary pattern.
      Considering the glucose responses to the same food are largely heterogeneous among people,
      this study integrates the concepts of precision nutrition and N-of-1 design. The study also
      aims to explore differences in brain structure and function between participants with
      different Body Mass Index (BMI) from the perspective of gut-brain axis.
    

Detailed description: 
      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.
    

Intervention name(s): refined carbohydrate breakfast; whole grain breakfast; intermittent fasting
Intervention type(s): Other; Other; Other
Intervention description(s): After wearing CGM on Day 1, participants will be provided with breakfast A once daily on Day 2, Day 5 and Day 6. Breakfast A contains white bread (50g) and milk powder (25g). Since lunch and dinner would serve as wash-out meals, participants will be free to choose food but provide a record of their diets.; After wearing CGM on Day 1, participants will be provided with Breakfast B once daily on Day 3, Day 4 and Day 7. Breakfast B contains plain oats (35g) and milk powder (25g). Since lunch and dinner would serve as wash-out meals, participants will be free to choose food but provide a record of their diets.; The period during Day 8 to Day 13 is intermittent fasting period. Participants will experience the moderate fasting on Day 9 and Day 12, which means their daily energy intake is expected to be controlled within 500-600 kcal limit. In these two days, participants will be provided with all three meals. Percentages of macronutrients of provided meals will follow the Recommended Dietary Health guidelines for Chinese residents. The oral glucose tolerance test (OGTT) will be conducted in the morning on Day 8 and Day 13, to test short-term impact of IF intervention on individuals' glucose tolerance. The breakfasts on Day 10 and Day 11 will be the same as that in fasting days. Other meals will be wash-out meals.
Other intervention name(s): Breakfast A; Breakfast B; IF
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: Glucose Metabolism; Intermittent fasting; Personalized Nutrition; Brain; Gut Microbiome