GHRL and obesity due to melanocortin 4 receptor deficiency: Stress is proposed to contribute to overweight and obesity through cognitive processes, behavioral effects, physiological changes in the hypothalamic–pituitary–adrenal axis, and promotion of the production of biochemical hormones and peptides such as leptin, ghrelin, and neuropeptide Y [37]; behavioral effects include overeating, reduced sleep quality, and increased physical inactivity.