The goal of this clinical trial is to investigate whether fasting timing has a significant effect on postprandial glycemic responses in healthy adults. The main questions it aims to answer are: 1. Whether fasting timing has a significant effect on postprandial insulin actions and plasma glucose concentration. 2. Whether fasting timing could modulate the glycemic metabolome and circadian rhythms in healthy individuals. Participants will get the two interventions: No-dinner: breakfast at 7.30 a.m., lunch at 1.00 p.m. and no dinner; No-breakfast: no breakfast, lunch at 1.00 p.m. and dinner at 8.00 p.m.
A randomized, crossover study design is used with 2 intervention days and a 6-day washout period, to evaluate the effects of early and late fasting on postprandial glucose responses in healthy adults. Randomization was performed by the Fudan staff with a block size of 2 using a balanced design using computer-executed software. The primary endpoint is the fasting and postprandial blood glucose, insulin, and continuous glucose monitoring after fasting. Secondary endpoints include postprandial blood lipids, clock gene expressions in peripheral blood cells, and non-targeted postprandial plasma metabolome. The 2 intervention days include a no-breakfast day and a no-dinner day. The diets before, during, and after the intervention day was designed according to Dietary Guidelines for Chinese Residents (2022), and the energy distribution of three meals is 1:1:1, with the energy percentage of carbohydrate, protein, and fat being 55%, 15%, and 30%, respectively. The time of breakfast, lunch, and dinner is 7.30 a.m., 1.00 p.m., and 8.00 p.m., respectively. All participants are instructed to follow their natural dietary plans in the wash-out period, and the food intakes and sleep circle were recorded by a modified food frequency questionnaire (FFQ).
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
SINGLE
Enrollment
The day before intervention day, all participants will be provided with 3 nutritionally balanced meals which are designed by the investigators. On the no-breakfast intervention day, participants are instructed to fast and only be allowed to consume water until 1.00 p.m. and consume the above-designed lunch and dinner at 1.00 p.m. and 8.00 p.m. Additionally, all participants are informed that they are only allowed to consume water between meals and before receiving breakfast at 7.30 a.m. the following day.
The day before intervention day, all participants will be provided with 3 nutritionally balanced meals which are designed by the investigators. On the no-dinner intervention day, participants are instructed to consume the above-designed breakfast and lunch at 7.30 a.m. and 1.00 p.m., and no dinner. Additionally, all participants are informed that they are only allowed to consume water between meals and before receiving breakfast at 7.30 a.m. on the following day.
Shanghai Institute of Planned Parenthood Research Hospital
Shanghai, Shanghai Municipality, China
Change from fasting to postprandial postprandial blood glucose
The primary endpoint is fasting and postprandial blood glucose with hexokinase tests.
Time frame: Blood samples collected before and after 2 hours at lunch on the no-breakfast day; blood samples collected before and after 2 hours at next day breakfast on the no-dinner day
Change from fasting to postprandial insulin
Fasting and postprandial insulin will be tested by ELISA KIT.
Time frame: Blood samples collected before and after 2 hours at lunch on the no-breakfast day; blood samples collected before and after 2 hours at next day breakfast on the no-dinner day
Results of continuous glucose monitoring
Continuous glucose will be monitored by Abott glucose monitor.
Time frame: From the day before the first intervention day and the wash-out period till the day after the second intervention day (10 days in total)
Change from fasting to postprandial blood lipids
Fasting and postprandial total-, HDL-, LDL-cholesterol, triglyceride will be tested.
Time frame: Blood samples collected before and after 2 hours at lunch on the no-breakfast day; blood samples collected before and after 2 hours at next day breakfast on the no-dinner day
Analyzes of clock gene expression in peripheral blood cells (PBC)
Clock gene expression in PBC will be evaluated by RT-PCR.
Time frame: PBC samples collected before and after 2 hours at lunch on the no-breakfast day; blood samples collected before and after 2 hours at next day breakfast on the no-dinner day
Analyzes of postprandial plasma metabolome
Non-targeted plasma metabolites will be tested by LC-MS-MS after 2 hours of each meal.
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Time frame: Blood samples collected at 2 hours after each meal