The researchers hope that their discovery may lead to the development of a drug that could help control appetite and weight.
Marina Picciotto, lead author of the study, said: "Ultimately, we would like to help people maintain their body weight when they kick the [smoking] habit and perhaps help non-smokers who are struggling with obesity."
According to the researchers, nicotine sets off a reaction in the brain that tells the body it is satiated.
The research, which was published in the journal Science, showed that the hypothalamus was affected when people smoked.
A study by the University of Washington has revealed that eating a high fat diet leads to inflammation of the hypothalamus.
This can interfere with the body's ability to control body weight, meaning that obese patients often find it hard to lose weight.