This article determines whether obesity can be linked to detrimental changes in the brain. It also discusses the properties of adipokines that lead to the pathology of the brain. It tries to relate the disease to the capacity of adipokines that enter the blood–brain barrier as opposed to adipokines that cannot. It further discusses the effect of adiponectin and leptin on dementia. The gene discussed is LEP; the disease is obesity due to melanocortin 4 receptor deficiency.