Thus, lepton activates several downstream neural pathways that alter the foraging behavior and metabolism. However, lepton deficiency, that occurs in conjunction with the loss of adipose tissue, stimulates appetite and induce other adaptive responses, such as inhibition of the hypothalamic thyrotrophic releasing hormone (thyrotrophic-releasing hormone TRH) and gonadotropin releasing hormone (gonadotropin-releasing hormone, Gnarl).
There are various cytokines such as tumor necrosis factor alpha (tumor necrosis factor α, TNF-α), interleukin (IL) 6 (IL-6), IL-1, interferon gamma (IFN-γ), the factor ciliary neurotropic (ciliary neurotropic factor, CNTF), and leukemia inhibitory factor (leukemia inhibitory factor, LIF), which can induce cachexia. In addition to such action, these factors can cause fever and depress myocardial function, modulate inflammatory and immune responses, and stimulate several specific metabolic alterations.
The TNF-α for example, preferentially mobilizes fat, but respects the striated muscle. The concentrations of one or more of these cytokines may be elevated in individuals with cancer, sepsis, chronic inflammatory disorders, AIDS and congestive heart failure.
Weight loss occurs when energy intake exceeds the calories available for that purpose. In most individuals, about half of the energy of the food is used as basic as the body temperature conservation function. In a 70 kg, BMR consumes about 1800 kcal / day. About 40% of calories consumed during the year, although athletes may use more than 50% when performed in intense degree. About 10% of the caloric intake is used for food thermogenesis, process in which the energy is consumed in the digestion, absorption and metabolism of foods.