According to a recent study by California Grapefruit Growers Cooperative, grapefruit juice may be just as effective as type 2 diabetes drug, metformin, at lowering blood glucose.
Researchers fed six groups of mice a variety of liquids, including sweetened diluted grapefruit juice, sweetened water, and water that contained metformin. The results were surprising. The mice who were fed a high-fat diet, which is typical of the average American, and drank grapefruit juice lost 18% more weight than those drinking sweetened water. They had a 13-17% drop in blood glucose levels and threefold decrease in insulin levels. The mice drinking grapefruit juice had glucose-lowering effects that were equally comparable as the mice who sipped on metformin.
You may have to drink a lot to get those prescription-level effects, though. The amount of grapefruit juice used in the mice study equates to four cups a day in people, the study says.
This isn’t the only benefit of drinking the bitter fruit juice. A study from the University of California, Berkeley found that drinking grapefruit juice with a high fat diet could lower the amount of weight gain by almost a fifth.
The Grapefruit Diet, where those wanting to lose weight drink a glass of juice with every meal, has been around since the 1930s, but was popularized in the 1970s.