July 25, 2021

Does the Grapefruit Diet Work?

Examining the eating plan’s fat-burning claims

half of a grapefruit sitting in a bowl

One thing is undisputed about the grapefruit diet: It certainly has staying power.


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The fad diet debuted in the 1930s amidst claims that its namesake fruit contains fat-burning enzymes that melt off pounds. Nearly a century later, it continues to draw attention and followers.

The eating plan (surprise, surprise) puts a big emphasis on a certain softball-sized citrus fruit. Grapefruit lands a high-profile role in every meal – breakfast, lunch and dinner.

The short-term diet’s main selling point is that it can help you lose 10 pounds during a 10- to 12-day detox. So is there any juice to that claim? Let’s squeeze out some information with dietitian Lauren Sullivan, RD.

What can you eat on the grapefruit diet?

For starters, you’ll chow on grapefruit – and lots of it.

Most versions of the diet include half a grapefruit with each meal of the day. The plans often allow you to sub in grapefruit juice if you’re feeling adventurous or don’t want to deal with a saw-toothed spoon.

After that, the primary focus of the diet is cutting waaaaay back on calories. Some plans suggest limiting yourself to as little as 800 calories in a day. That’s less than half of what is recommended for a healthy diet.

“Calories are energy for your body,” explains Sullivan. “Think of it like gasoline in your car. If you’re not fueling up properly, your engine is going to sputter.”


Other hallmarks of the classic grapefruit diet include eating foods rich in protein and high in fat and cholesterol. (Think eggs and red meat). The diet also tends to frown upon sugars and carbohydrates.

A sample meal on the grapefruit diet might include:

  • Half a grapefruit or 8 ounces 100% grapefruit juice without adding sugar.
  • Salad or a red or green vegetable cooked in butter or spices.
  • Meat or fish cooked in any manner.
  • One cup of coffee or tea without cream or sugar.

There is no one grapefruit diet, though, so guidelines tend to change plan to plan. The eating plan also carries several aliases, including the Hollywood diet.

Does grapefruit really melt fat?

Grapefruit offers many wonderful qualities, but being a miracle fat burner isn’t one of them. “It’s a healthy food,” says Sullivan. “It’s not magic, though.”

The fruit, however, does deserve consideration for your weight loss toolbox. A 2006 study showed that it “would appear reasonable” to include grapefruit in a diet designed to shed pounds. A 2011 study came to much the same conclusion.

Here’s why: Grapefruit is roughly 88% water, so eating it with meals tends to make you feel full faster. That, in turn, makes you eat less. (The nutrition pros call that concept “preloading.”)

As for the grapefruit diet’s quick weight loss claims, that’s more a byproduct of severely slashing calories. “You lose weight on the plan because you’re not eating as much,” says Sullivan. “It’s that simple.”


Grapefruit and medications

A word of caution for anyone considering the grapefruit diet: It’s definitely not a good idea if you’re on certain medications, including statins that help regulate your cholesterol.

Grapefruit contains a chemical compound that interferes with your body’s ability to process some medications. That affects the way the medicines work, leading to some serious health concerns.

The U.S. Food and Drug Administration requires warnings on some medications related to their use with grapefruit or grapefruit juice. If you’re on a medication, ask your healthcare provider if grapefruit is OK to include in your diet.

Benefits of grapefruit

Don’t let the dubious claims about the grapefruit diet shape your opinion on the tropical fruit, says Sullivan. Overall, grapefruit offers an impressive nutritional resume. Highlights include:

  • Serving as an excellent source of Vitamin C and Vitamin A.
  • Packing a high fiber content that can boost heart health.
  • Cancer-fighting antioxidant properties.
  • A low score on the glycemic index, meaning it doesn’t cause blood sugar levels to spike.

On top of that, grapefruit packs a lot of taste without a lot of calories.

“Grapefruit is worth having in your diet,” says Sullivan, “but don’t base your whole diet plan around it.”

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