Grapefruit juice may stem weight gain
New research from the University of California, Berkeley, found that mice given pulp-free grapefruit juice while being fed a high-fat diet gained 18 percent less weight than their counterparts that drank only water. The grapefruit mice also showed improved levels of glucose, insulin, and a type of fat called triacylglycerol.
The researchers randomly divided mice into six groups, including a control group that drank only water. Those drinking grapefruit juice got a mixture diluted with water at different concentrations, and sweetened slightly with saccharin to counteract grapefruit's bitterness. The researchers also added glucose and artificial sweeteners to the control group's water so that it would match the calorie and saccharin content of the grapefruit juice. At the end of the study period, the mice that ate the high-fat diet and drank diluted grapefruit juice not only gained less weight than their control counterparts, but they also had a 13 to 17 percent decrease in blood glucose levels and a threefold decrease in insulin levels.
Continuing the study, the researchers gave one group of mice naringin, a bioactive compound in grapefruit juice that has been identified as an agent in weight loss, and another group metformin, a glucose-lowering drug often prescribed for those with type 2 diabetes. The mice were fed a diet that was either 60 percent fat or 10 percent fat for 100 days, and their metabolic health was monitored throughout the study. The results showed that grapefruit juice lowered blood glucose to the same degree as metformin.
The study did not find as much of an impact on mice that ate a low-fat diet in terms of weight-loss, but those mice still had a decrease in insulin levels.