Fasting Effects on Metabolism and Immunity Study in Human

As a historic practice, fasting has a place in religion, culture and modern medicine. In recent years, studies have found that moderate food interruption can positively affect metabolism, immunity, and brain function. It can promote cellular autophagy, improve insulin sensitivity, reduce inflammation, and may protect brain health. Intermittent fasting is thought to improve metabolic health, reduce the risk of obesity and type 2 diabetes, and promote cellular self-repair by regulating signaling pathways. Food fasting also improves insulin sensitivity, reduces blood glucose, reduces inflammatory markers, and improves fat oxidation rate, contributing in the prevention and treatment of metabolic diseases. Moreover, food fasting can regulate immune cell function, reduce chronic inflammation, and may regulate immune function by affecting gut microbiota diversity. In terms of brain function, fasting may improve cognitive function by promoting neuroplasticity and enhancing neuroprotective mechanisms. However, most of the existing studies focus on animal experiments, lack large-scale human clinical trials, and the mechanism of feeding is not completely clear. This study will explore the effects of complete fasting for 1 week (but can feel free to drink water) on human immune function, metabolic indicators and brain function in human, and analyze its change mechanism from a multi-omics perspective and/or other ways, so as to provide new data support for understanding the biological mechanism of fasting, and promote its application in disease prevention and treatment.

• The change in concentration of intestinal flora species，rate of change in bacterial diversity，abundance of functional genes in subjects' stool samples from T1 to T2, T3, T4, and T5. [Time frame: T1 (Baseline/Pre-fasting): Day 0; T2 (End of one week fasting): Day 8; T3 (End of one week re-feeding): Day 15; T4 (End of four weeks re-feeding): Day 36; T5 (End of twelve weeks re-feeding): Day 92.]
• The change of brain function from T1 to T2, T3, T4, and T5. [Time frame: T1 (Baseline/Pre-fasting): Day 0; T2 (End of one week fasting): Day 8; T3 (End of one week re-feeding): Day 15; T4 (End of four weeks re-feeding): Day 36; T5 (End of twelve weeks re-feeding): Day 92.]
• The change of blood lipid levels from T1 to T2, T3, T4, and T5. [Time frame: T1 (Baseline/Pre-fasting): Day 0; T2 (End of one week fasting): Day 8; T3 (End of one week re-feeding): Day 15; T4 (End of four weeks re-feeding): Day 36; T5 (End of twelve weeks re-feeding): Day 92.]
• The change of homocysteine levels from T1 to T2, T3, T4, and T5 [Time frame: T1 (Baseline/Pre-fasting): Day 0; T2 (End of one week fasting): Day 8; T3 (End of one week re-feeding): Day 15; T4 (End of four weeks re-feeding): Day 36; T5 (End of twelve weeks re-feeding): Day 92.]
• The change of insulin levels in subjects' blood samples from T1 to T2, T3, T4, and T5. [Time frame: T1 (Baseline/Pre-fasting): Day 0; T2 (End of one week fasting): Day 8; T3 (End of one week re-feeding): Day 15; T4 (End of four weeks re-feeding): Day 36; T5 (End of twelve weeks re-feeding): Day 92.]
• The change of thyroid function level from T1 to T2, T3, T4, and T5. [Time frame: T1 (Baseline/Pre-fasting): Day 0; T2 (End of one week fasting): Day 8; T3 (End of one week re-feeding): Day 15; T4 (End of four weeks re-feeding): Day 36; T5 (End of twelve weeks re-feeding): Day 92.]
• The change of body fat percentage from T1 to T2, T3, T4, and T5. [Time frame: T1 (Baseline/Pre-fasting): Day 0; T2 (End of one week fasting): Day 8; T3 (End of one week re-feeding): Day 15; T4 (End of four weeks re-feeding): Day 36; T5 (End of twelve weeks re-feeding): Day 92.]