GCG and metabolic syndrome: Since plasma active GLP-1 level increase significantly after meal ingestion and since it is responsible for a large proportion of postprandial insulin secretion, we can not ignore the possibility that fasting active GLP-1 is not an effective predictor of the onset of insulin resistance and metabolic syndrome in apparently healthy Chinese, postprandial plasma active GLP-1 may play a more important role than fasting plasma active GLP-1 in predicting incident metabolic syndrome.