U.S. scientists have discovered factors that make smokers thinner than non-smokers. The findings, said the Agence France Presse in a report proved that nicotine can serve as an ‘appetite suppressant in the brain’ that will prevent users from gaining weight.

According to the AFP, the study conducted by the University of Yale detailed ways how nicotine can activate hypothalamus, a kind of neuron of the brain that controls what the body need or does not need.

This neuron explained Marina Picciotto from Yale University can tell if the body needs more food or not.

"Many people say they won't quit smoking because they'll gain weight. Ultimately, we would like to help people maintain their body weight when they kick the habit and perhaps help non-smokers who are struggling with obesity," the Yale professor of neurobiology and pharmacology explained of the study recently published in the journal Science.

The study began when researchers were working nicotinic acetylcholine receptors found on the surface of the hypothalamus. The scientists noted AFP wanted to test if depression can be treated by the experimental drug.

The study’s turning point came with the use of the drug on the experiment using mice.

"He noticed that mice given the drug ate less than those not on the medication," the AFP said, citing the study.

These initial findings resulted in another scientific investigation conducted by researchers from Carleton University in Ottawa, Canada and the University of Hawaii.

The joint study then showed that the experimental drug allows the nicotine receptor that dictates the neurons of the brain called hypothalamus, also known as Pro-Opiomelanocortin or POMC cells that the body needs no more food.

"This suggests it is possible to get the effect of appetite suppression without also triggering the brain's reward centers," Picciotto was quoted as saying by the AFP.

"Identifying this receptor is important for the understanding of the mechanisms related to addiction, weight and smoking."

With the increasing number of cases of obesity in the U.S., the scientists are looking into the relationship between the smoking and how it can help prevent obesity - - a cause that even the U.S. First Lady Michelle Obama has joined to fight against.