AKT1 and obesity due to melanocortin 4 receptor deficiency: Lower lipid accumulation and the hypolipidemic effect after B. natto supplementation are probably due to an increased expression of Ppar-α and decreased expression of Srebp-1c, while the anti-obesity effects are due to an increase in p-PI3K/PI3K, p-AKT/AKT, and IRS-1 protein expression.