INS and obesity due to melanocortin 4 receptor deficiency: Rats fed a low-fat diet supplemented with BCAAs do not develop insulin resistance.30 Several studies suggested that BCAA supplementation or BCAA-rich diets are beneficial for promoting lean body mass in obesity or catabolic disorders or for increasing satiety for body weight loss.29 A study on the synergistic effect of exercise and BCAAs on brain structure and function found that BCAA and exercise decreased body weight, decreased fasting insulin levels, and improved circadian rhythms.