Food plays a crucial role in determining blood glucose levels, especially in people with type 2 diabetes. Precision nutrition, which involves individually tailored dietary interventions, can be a powerful tool in managing blood glucose levels in people with type 2 diabetes. Previous studies found that changes in gut microbiota resulted from the dietary intervention, such as plant-based diet, might subsequently lead to different glycemic responses, and then different health outcomes. In this study, the investigators will characterize the blood glucose dynamics and gut microbiota of individuals with type 2 diabetes. They aim to assess the influence of plant-based diet on gut microbiota; they will also investigate the influence of gut microbiota on glycemic responses. Additionally, a series of individual N-of-1 trails will be integrated to compare the effects of a white bread breakfast and a whole wheat bread breakfast on glucose metabolism at the individual level.