Effects of Time-Restricted Fasting on the Postprandial Glycemic Responses

Effects of Time-Restricted Fasting on the Postprandial Glycemic Responses in Chinese Adults: A Randomized Crossover Study

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).

Inclusion Criteria:

1. Both men and women are eligible.
2. Age: 18-40 years old.
3. Healthy adults: no history of diabetes mellitus, no use of hypoglycemic drugs, no insulin injection.
4. All participants have a good sleep circle, with no somnipathy.

Exclusion Criteria:

1. Severe mental illness or other major medical comorbidities and autoimmune diseases (e.g., chronic renal failure, cardiovascular diseases, or cancer)
2. Skipping breakfast or dinner more than 10 times within 6 months.
3. Following a special diet, currently on weight loss medication, using sleeping medications.
4. Pregnancy or to be pregnant.