IL6 and obesity due to melanocortin 4 receptor deficiency: Obesity and HFD lead to systemic and central inflammation with elevated circulating IL-12 and IL-6, both of which have been linked to impaired processing speed and executive function, even independently of metabolic risk factors (Gregor & Hotamisligil, 2011;Thaler & Schwartz, 2010;Trolloret al., 2012).