The study conducted on mice found that mice fed a high-fat diet gained 18 percent less weight when they drank clarified, no-pulp grapefruit juice compared with a control group of mice that drank water.
"There are many active compounds in grapefruit juice, and we don't always understand how all those compounds work," noted Andreas Stahl, professor of nutritional sciences and toxicology at the University of California, Berkeley in the US.
"The grapefruit juice lowered blood glucose to the same degree as metformin. That means a natural fruit drink lowered glucose levels as effectively as a prescription drug," said Joseph Napoli from the same university.
The mice that ate the high-fat diet and drank diluted grapefruit juice not only gained less weight than their control counterparts, they also had a 13 to 17 percent decrease in blood glucose levels as well as a three-fold decrease in insulin levels.
"These results, based on controlled experiments, warrant further study of the potential health-promoting properties of grapefruit juice," concluded Stahl.
The study appeared in the journal PLOS ONE.