Like clothing and hairstyle trends, fad diets come and go, only to return in slightly new variations years later. Perhaps one of the best-known diets that somehow keeps returning to the mainstream is the grapefruit diet.
Maybe you watched your mom or your grandmother religiously eat a grapefruit with one of those tiny spoons before every meal in an effort to lose weight. Or maybe you had a friend who would drink a glass of grapefruit juice each morning.
Despite the fact that science hasn’t proven the grapefruit diet to be effective, people continue to rely on this slightly sour citrus as a weight loss tactic.
What Is the Grapefruit Diet?
The grapefruit diet has been around in some form or another since the 1930s and endorses simply eating half a grapefruit before every meal. Other variations of the grapefruit diet will have you drink grapefruit juice instead of (or in addition to) eating the fruit itself. And then more restrictive variations require you to do that and stick to 800 calories per day, while cutting out most carbs.
Why grapefruit? Proponents believe that its enzymes can help you burn fat and magically help you lose weight. Some people (on the always-reliable Internet) even claim that it can help you lose 10 pounds in under two weeks.
What Do You Eat on the Grapefruit Diet?
You can eat pretty much anything on the grapefruit diet, as long as you eat half of a grapefruit beforehand. As far as diets go, whether it works or not, this one is pretty simple to follow!
However, if you’re sticking to the low-carb version of this diet, you need to eat your grapefruit and cut back on carbohydrates such as:
- Sugar
- Rice
- Pasta
- Potatoes
- Bread
But again, there aren’t any super specific guidelines when it comes to this part of the diet.
So far, researchers haven’t found any concrete evidence that the grapefruit diet can help you shed pounds; most results were correlative.
In a study from Louisiana State University researchers, obese adults were given either half a fresh grapefruit, eight ounces of grapefruit juice, grapefruit capsules, or a placebo. The groups who consumed half a grapefruit or drank eight ounces of grapefruit juice before each meal lost about 3.5 pounds in 12 weeks. The capsule group only lost 2.4 pounds, and the placebo group saw nearly no change.
Although the grapefruit groups saw some promising results, the researchers ultimately concluded that the “mechanism of this weight loss is unknown.”
Another study conducted by British researchers compared consuming grapefruit, grapefruit juice, or water before meals for 12 weeks. All three pre-meal options helped the study participants lose weight with no significant differences among the three, meaning the citrus was on par with the water.
Corroborating those results, a study from the journal Metabolism concluded that eating half a grapefruit before every meal for three weeks didn’t lead to significant weight loss compared to a placebo.
The only other studies that have found a direct connection between consuming grapefruit juice or extract and weight loss have been in mice. Unfortunately (in this very specific case), humans are not rodents.
Why Do People Think Grapefruit Helps With Weight Loss?
“Grapefruit is a big, filling thing. If you eat it, then you may eat less of your meal because your stomach is full of grapefruit,” says Denis Faye, M.S. “Plus, grapefruit has a weird taste and sort of blows out your taste buds, so you may eat less because things wouldn’t taste as good.”
In fact, you could replace the grapefruit with other foods and see similar results. “It’s like having a salad or vegetable soup before your meal,” says nutrition consultant Keri Gans, R.D.N., author of The Small Change Diet. It’s all low-energy-dense food that can fill you up before the main course.
“But I don’t buy that there are special substances in grapefruit [to help you burn fat],” Faye says.
Drawbacks of the Grapefruit Diet
“I believe in variety and not eating the same things over and over,” Faye says. “Front-loading with a healthy, lower-calorie food so you eat less is a weight-loss strategy, but you still have to make smart choices after. If you eat a grapefruit and then go get fast food, you won’t miraculously lose weight.”
People who take statins or blood pressure medication such as calcium channel blockers should also avoid the grapefruit diet, as these medications can have negative interactions with grapefruit.
Health Benefits of Grapefruit
Weight loss aside, there are indeed some health benefits of grapefruit. Half a medium grapefruit is mostly water and contains 37 calories and 1.4 grams of fiber. It also provides 45 mg of vitamin C (half the recommended daily value for men and 60 percent for women), which helps support a healthy immune system.
The Takeaway
While grapefruit certainly has a place as part of a balanced diet, don’t think that by simply eating grapefruit or drinking grapefruit juice you will burn belly fat and slim down. To effectively lose weight and keep it off, you need to stick to the tried and true formula of exercising regularly and eating a well-rounded diet — grapefruit included, or not.
