In my years of writing on health and fitness topics, I’ve covered my fair share of fad diets and frankly ridiculous ideas that have permeated my realm. One that keeps coming back, however, is the thinking that grapefruit juice helps weight loss. And I will readily admit that I have been critical of this idea in the past. Thanks to some new research, though, it seems like I might have to be a little more open-minded.

First, though, I’m going to stubbornly defend my previous stance.

What Was Wrong

Over the past several years, grapefruit juice has been touted by a huge number of celebrity and fad diets as a weight loss miracle. And I have vehemently disagreed. My primary objection, though, has been directed at the way these diets were designed and how proponents claimed grapefruit juiced worked.

First, the diets were often extreme fasts or cleanses that required you to eat nothing but grapefruits for several days. Of course you’re going to lose weight, you’re at a massive caloric deficit. The infamous “Twinkie Diet” dramatically demonstrated that even if you were to eat nothing but junk food you would lose weight as long as you restricted your calorie intake.

Then there’s the issue of rebound. These grapefruit-centric crash diets were only designed to be followed for a few days and do not sustain lasting weight loss. Statistically, once you return to eating real food, you’re extremely likely to not only regain the weight you lost but also gain a few extra pounds as well.

My second cause for complaint is the supposed mechanism by which grapefruit was claimed to help with weight loss: Acid. In the past, supporters asserted that the high acid content of grapefruit literally burned your fat away. This is both impossible and wrong.

So, how does grapefruit help to reduce body weight according to this new body of research?

What’s Really Going On

For this study, conducted at the University of California – Berkeley, mice were divided into six different groups. The control group was given water that had been modified to have the same amount of calories and sugar as grapefruit juice. The juice used in the study was diluted and sweetened.

Other groups were given either an isolated form of naringin – a compound found in grapefruit juice – or a prescription glucose-lowering drug called metformin.

The mice were placed on either a high-fat (30 percent) or low-fat(10 percent) diet throughout the 100-day study. At the end of the study, two interesting findings surfaced. Most noticeably, the mice that were fed a high-fat diet and given grapefruit juice gained the least amount of weight when compared to the other groups.

Of course, it could also have been that the benefits were present in the low-fat group but simply more subtle. More research is needed to fully understand this connection.

The researchers also noticed that grapefruit juice had the same beneficial effects on blood sugar that the prescription drug.

It is very important to note, though, that grapefruit juice didn’t help the mice actually lose any weight; The juice simply stopped them from gaining as much. This means that grapefruit juice is not a magic bullet but could have it’s place in an otherwise healthy routine.

Cautions and Such

Although grapefruit juice showed a lot of potential when it comes to controlling blood sugar, you should never self-medicate if you have a condition. You also should not combine grapefruit juice with a prescription medication without talking to your doctor.

It is also worth mentioning that this study was funded by the California Grapefruit Growers Cooperative. Despite this, the researchers asserted that the backers had no influence on the design or outcome of the study.

Sources

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0108408

http://www.sciencedaily.com/releases/2014/10/141008153626.htm