In conclusion, the replacement of 70% dietary casein protein with the equivalent quantity of protein derived from HMDP or HMPH in mice with high-fat diet-induced obesity and insulin resistance significantly improved semi-fasting and fasting blood glucose levels, oral glucose tolerance, insulin sensitivity and pancreatic β-cell function, along with the reductions in blood insulin, leptin and free fatty acid levels. This evidence concerns the gene INS and obesity due to melanocortin 4 receptor deficiency.