CLOCK and Obesity: regulate the host metabolism via glucose and lipid metabolism; Lactobacillus and Bifidobacterium help to maintain weight; Prevotella facilitates peripheral clock adjustment; Prevotellaceae, Bacteroidia, and Dialisster control the circadian system that regulates intestinal physiology and systemic metabolism; Prevotella and Bacteroidia improve circadian rhythmicity; Bacteroidia exhibits an anti-obesity response (Table 2).