For example, feeding mice leucine has been shown to reduce high-fat-diet-induced hyperglycemia, obesity, and hypercholesterolemia [38], and an orally administered mixture of ketogenic amino acids including leucine, isoleucine, valine, threonine, and lysine has been demonstrated to improve insulin sensitivity in elderly patients with type-2 diabetes [39]. This evidence concerns the gene INS and obesity due to melanocortin 4 receptor deficiency.