Whenever we experience painful sensation, the brain produces natural painkillers, chemically similar to strong drugs such as morphine, oxycontin, and oxycodone. However, natural drug endogenous opioids in the brain also plays key role to help regulate the body's energy level, says new research.

While suffering pain, human brain produces a unique natural painkiller that could relieve the pain as chemical drug morphine. Natural painkiller not only relieves from the immediate pain, but also helps to regulate the body balance by maintaining energy levels.

The scientists from the University of Turku in Finland took 10 healthy men and tested their endogenous opioids released in the brain. Researchers injected these subjects with a radioactive substance that binds to opioids receptors, making it possible to view the receptors' activity with the help of positron emission tomography (PET)

The study proved the presence of natural painkiller in the brain after they finished eating a palatable meal of pizza. Astonishingly, when men ate a meal of extremely less enticing but nutrititious food called goo, the brain released even more of the endogenous opioids. Although pizza gives more taste than goo, opioids release didn't seem to relate to the taste of the meal, reported research.

"I would have expected the opposite result," said Paul Burghadt, a researcher at Wayne State University. Though he didn't involve in the study, he made the review of the study.

The previous research showed that obese people released relatively fewer opioids receptor. However, that receptor level comes to normal with weight loss.

"Maybe when people overeat, endogenous opioids released in the brain constantly bombard the receptor," said Paul.

More opioids flooded the brain after the consumption of goo was the matter that they could not explain precisely; the researchers conjectured that rapid digestion of food might have caused more released of opioids receptor/ chemicals at the time of the scan.

" One possibility is that the opioids system is triggered by the satisfaction of a full stomach and replenished energy," said lead author Lauri Nummenmaa. "The most interesting thing is that eating triggered the system even in the absence of sensory pleasure," said Nummenmaa.