Oxidative stress may play an important role in the development of obesity through several mechanisms including damage to cells/cell components and tissues in the body, especially to adipocytes and mitochondria, leading to excessive fat accumulation and reduced fat burning, causing chronic inflammation, which can affect carbohydrate and lipid metabolism and cause insulin resistance and influence hormone levels in the body, including hormones that regulate hunger and satiety (ghrelin, leptin, cholecystokinin, neuropeptide y, etc.). This evidence concerns the gene LEP and obesity due to melanocortin 4 receptor deficiency.