Soo-Jong Um, Ji-Cheon Jeong and colleagues at Sejong University in Seoul said black pepper and the black pepper plant were used for centuries in traditional Eastern medicine to treat gastrointestinal distress, pain, inflammation and other health disorders.
Despite the long medicinal history, scientists know little about how the spice works on the innermost molecular level.
The study, published in the Journal of Agricultural and Food Chemistry, found piperine -- the pungent-tasting substance that gives black pepper its characteristic taste -- blocks the formation of new fat cells.
Using laboratory studies and computer models, the researchers found piperine interferes with the activity of genes that control the formation of new fat cells.
Piperine might also set off a metabolic chain reaction that helps keep fat in check in other ways, the researchers said.