RESUMO
BACKGROUND: Obesity, diabetes mellitus may be related to the health, the relationship and the physiological capacity of the production of thyroid hormones (TH), triiodothyronine (T3) and thyroxine (T4). OBJECTIVES: The main aims of this review are to describe the relationship between obesity, appetite, weight management, hormonal mechanisms of diabetes mellitus and hypothyroidism post-bariatric surgery. METHODOLOGY: An in-depth literature search was conducted to identify scientific studies, which analyzed the correlation between diabetes mellitus and hypothyroidism post-bariatric surgery. RESULTS: Bariatric surgery decreases hypothyroidism, reduces the need for pharmacological action (such as levothyroxine), controls the weight and body fat and increases the sensitivity to leptin and insulin. CONCLUSION: The reduction of the stomach and intestine by bariatric surgery is an evolutionary and beneficial action, because it may lead to a drastic decrease on numbers of conditions such as diabetes, obesity, hypothyroidism, and others. Thus, new studies should also focus on patients' post-operatory conditions, such as lifetime, regulation and functioning of organs after reduced nutrition, and consumption and delivery of nutrients to health maintenance.