Hence, psychological (e.g., personality traits, resilience, coping strategies), genetic (e.g., 5-HTT, BDNF, FTO), behavioral (e.g., diet, smoking, exercise, sleep quality), socioeconomic and environmental (e.g., family income, education, neighborhood, exposure to contaminants) factors should be explored in order to identify phenotypes in which chronic stress predisposes to obesity development and vice versa. This evidence concerns the gene FTO and obesity due to melanocortin 4 receptor deficiency.