Any significant weight loss that a previously healthy person usually has not deliberately sought to indicate the existence of a systemic disease. Therefore, whenever you make the interrogation clinician should ask about weight changes as a loss of 5% of body weight in a period of six to 12 months require immediate implementation of additional studies.
Physiological regulation weight
Normal individual maintained their body weight at a predetermined level of remarkable stability, given how much change daily caloric intake and activity level. Due to the physiological importance has conserve energy reserves, it is difficult to lose weight and keep it off voluntarily.
The appetite and metabolism are regulated by a complex network of neural and hormonal factors. Hypothalamic centers of hunger and satiety are essential in these phenomena. Some neuropeptides, such as corticotropin releasing hormone (corticotropin-releasing hormone, CRH), the melanocyte stimulating hormone alpha (α-melanocyte stimulating hormone, α-MSH) and related transcript cocaine and amphetamines (cocaine and amphetamine-related transcript, CART) produce anorexia by acting on the central nervous system (CNS) in satiety centers. Gastrointestinal peptides ghrelin, glucagon, somatostatin and cholecystokinin are the ones that cause satiety and decrease food intake. Hypoglycemia suppresses the action of insulin, which lowers glucose utilization and inhibits the action of the satiety center.
Leptin produces adipose tissue and contributes significantly to the preservation of homeostasis weight (long-term) to act in the hypothalamus to reduce food intake and increase energy consumption. Leptin suppresses the expression of hypothalamic neuropeptide Y, which is a potent stimulator of appetite, and enhances the expression of alpha-melanocyte stimulating hormone, which through melanocortin receptor (MC4R) exerts the effect of mitigating the appetite. Thus, leptin activates several downstream neural pathways that alter the foraging behavior and metabolism. However, leptin deficiency, which occurs in conjunction with the loss of adipose tissue, stimulates appetite and induce other adaptive responses, such as inhibition of the hypothalamic thyrotropin releasing hormone (thyrotropin-releasing hormone TRH) and gonadotropin-releasing hormone (gonadotropin-releasing hormone, GnRH).