LPA and obesity due to melanocortin 4 receptor deficiency: In this study, the effects of Roux-en-Y gastric bypass surgery (RYGB) and an intensive lifestyle intervention, including caloric restriction and exercise, on plasma Lp(a) and FA levels in patients with obesity were compared, and it was also examined whether possible effects on plasma Lp(a) levels were mediated by changes in plasma FA levels.