In a recent study investigating the relationship between Hp phenotype and diet-induced weight loss, the Hp1-1 phenotype was associated with greater improvements in abdominal obesity, plasma insulin levels, and insulin resistance when compared to the Hp2-1 and Hp2-2 phenotypes in women with obesity; however, weight/BMI change was not different between phenotypes [36]. This evidence concerns the gene HP and obesity due to melanocortin 4 receptor deficiency.