When you lose weight, the body preserves energy by slowing metabolism and increasing hunger. Scientists recently uncovered how this process works. An empty stomach secretes a hormone called ghrelin that sends messages to the hunger center in the brain to slow metabolism, impair fat
use and promote hunger. Some people secrete more ghrelin than others, which makes them fat. Researchers from Scripps Institute in San Diego developed a vaccine that tricks the body into making antibodies to neutralize ghrelin.
Injecting rats with the anti-ghrelin vaccine decreased feeding efficiency (energy absorbed compared to energy consumed), body fat and weight gain compared to unvaccinated animals. The vaccine didn't cause any loss of lean mass (mainly muscle). They concluded that vaccination against ghrelin can slow weight gain in rats by decreasing feeding efficiency. Ghrelin is only one of more than 15 chemicals in the body that control appetite and metabolic rate, so suppressing it won't cure obesity. This is exciting research that may help stem the obesity epidemic.