Body WEIGHT, as determined by several key components, remains relatively stable over time. UNINTENTIONAL WEIGHT LOSS, defined as a decrease of more than 5% of usual body WEIGHT during a 6 to 12 month period, is an important predictor of morbidity and mortality. However, WEIGHT LOSS is a non-specific finding with multiple possible etiologies, that include organic, psychosocial, and idiopathic etiologies. A rational stepwise approach based on relevant data extracted from the history and physical examination, with special attention to psychological and social issues, is highly effective in establishing a diagnosis and determining effective management. Treatment should be based on the results of the tests and each patient’s clinical situation.

Obesity is a multiple-factorial disease and a major challenge for the public health. Nowadays, prevalence of the disease is increasing in developed and developing countries due to changes in the peoples’,lifestyle (1). General obesity and abdominal obesity are significantly associated to diseases such as cardiovascular diseases (CVD), gastrointestinal tract (GIT) diseases and cancers. In addition, obesity is an important risk factor for hypertension, type 2 diabetes and hyperlipidemia. It has recently been addressed that obesity is not only linked to medical consequences, but also it is associated to people’, s social statuses (2). In general, highenergy foods, changes in lifestyle, LOSS of physical activity, composition of intestinal microbiota and increased urbanization are the major causes of obesity (3). . .