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Slim down with Grapefruit Juice? Berkeley Study Adds Weight to Idea

December 16, 2014 By Dr. William S. Gruss, M.D.

If you’re planning on hitting up your favorite restaurant for a pepperoni pizza or cheeseburger and fries, you may want to swap your chocolate malt for grapefruit juice instead.

New research from UC Berkeley showed that mice who consumed sweetened grapefruit juice while consuming a diet high in fat may gain less weight than those who opted for sweetened water. The juice guzzling mice also had better metabolic health measures, insulin sensitivity and blood sugar levels.

Studies also found that the weight loss or gain was not affected by grapefruit juice when the mice were put on a low-fat diet. However, it did affect their sensitivity to insulin.

While the studies sound favorable when it comes to shedding pounds, it does come with several warnings. The California Grapefruit Growers Cooperative paid for the study. However, the researchers from Berkeley began the study with a lot of skepticism when it came to the power of this delectable citrus fruit.

They were so blown away by the end results of the study that they re-checked the sensors and calibrations to ensure that they were accurate.

The study was in the smaller range with only six mice being used to test their consumption of liquid, diet and nutrients. While the research may have shown the powerful results of grapefruit juice in mice, it doesn’t mean that it will prove just as beneficial to humans. However, the positive findings may show why grapefruits are typically featured in many of today’s fad diets.

The bitter flavors in grapefruit juice come from naringin. This powerful flavonoid is not a particular favorite of mice. The cause for the weight loss in previous studies that used both mice and grapefruit juice may have stemmed from the fact that the mice’s appetites were suppressed because of their disdain for the taste of grapefruit.

The Berkeley studies hoped to resolve this issues by sweetening the juice with saccharin first. They also gave the mice in the alternate group sugar water sweetened with saccharin and glucose. The number of calories was also the same as the juice that was sweetened.

Mice given grapefruit juice drank and ate similar amounts. However, after eating a diet higher in fat for approximately 100 days, the mice who consumed grapefruit juice had a weight reduction by as much as 18.5 percent than the rodents with the sweetened water. Their weight loss also became apparent after 15 days and significant enough by the time 78 days rolled around.

At the end of the 100 day study, the grapefruit juice laden mice were in much better metabolically than those who drank the sugar water. They also had less sensitivity to insulin, low fasting blood sugar numbers and a reduced level of liver triglycerides.

A follow-up experiment also allowed the mice to increase their girth before the grapefruit juice study was introduced. At the end of the 55 days, there was a noticeable weight reduction in the mice who consumed grapefruit juice as opposed to the ones who stuck to water. Their metabolic functioning was also much better.

The researchers then compared the effects of grapefruit flavonoid enriched naringin, grapefruit juice and diabetes pharmaceutical metformin. While all three of the treatments were found to reduce the blood sugar levels in mice, the grapefruit juice drinkers weighed less by as much as 14 percent after 100 days.

How grapefruit juice promotes weight loss isn’t exactly clear at this time. However, researchers did find that the juice drinking mice did express a particular protein that was crucial in regulating their metabolism. Grapefruit juice can also affect the way the body metabolizes specific pharmaceutical drugs in regards to allergies, cholesterol, anxiety and blood pressure. The problem is so serious that scientists are looking into a hybrid species of grapefruit that would be safe to consume with certain medications.

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