The results provide the first scientific evidence that the two obesity models have overall similar constipation phenotypes, such as excretion parameters, GI transit, histological structure of colon, and mucin secretion ability, but a significant difference in only the ENS regulatory factors, including the ICC number, neuron number, mAChRs expression, and their downstream signaling pathway, and serotonin receptors expression. This evidence concerns the gene MUC5AC and obesity due to melanocortin 4 receptor deficiency.