Obesity is a condition characterized by excess fat accumulation resulting from hypertrophy and /or hyperplasia of adipocytes, which is caused by consuming more energy than the body actually needs. This has some metabolic consequences. The concept of metabolic syndrome (MS) encompasses the clinical condition of the coexistence of some risk factors that contribute to the formation of type 2 diabetes and atherosclerotic cardiovascular diseases. The metabolic syndrome consists of increased waist circumference, elevated fasting blood glucose, hyperinsulinemia, disorders of lipid metabolism including low HDL cholesterol, hypertension, proinflammatory and protrombotic conditions. Two different causes can play a role in the etiology of metabolic syndrome, namely "adipose centered" and "diabetes centered" causes. At the center of all these metabolic changes is the increa-se in fat mass, which also plays a major role in the pathogenesis of insulin resistance. Lack of physical activity and consumption of high-calorie processed foods are important factors for the development of MS. In this article, the role of adipose tissue in the development of the metabolic synd-rome is underlined and it is shown that the common causal link between obesity and insulin resistance is inflammation. In addition, the prevalence of obesity and metabolic syndrome in Turkey and in the world is presented in the light of the literature. The importance of dietary therapy to reduce the risk of patients with cardiovascular disease with metabolic syndrome is also emphasized. Data from worldwide studies require that, in the XXI cen-tury, the metabolic syndrome including obesity and its complications must be considered as an epidemic.