What Is the Watermelon Diet, and Is It Safe?

Medically Reviewed
watermelons
Fads like the watermelon diet don't tell the whole truth about the risks of "detoxing."Evdokimov Maxim/Shutterstock

The watermelon diet may be 2022’s version of the 1970s trendy grapefruit diet. A lot of fad diets can thank a celebrity connection for their popularity — for the grapefruit diet, that was reportedly Brooke Shields. And for the watermelon diet, it’s Gabi Butler, who explained to her mom on an episode of the hit Netflix series Cheer?that she and a teammate were going on the watermelon diet as a cleanse for a few days.

Asked about the diet by Katie Krause on Extra in January, Butler said, “It's basically a watermelon fast. You're not actually fasting, because you're getting something in your stomach.” She added, “I will do it every once in a while when I feel like I've just been eating really bad, not only for my physical appearance but for my mental state, too … It’s not something that is unhealthy. It actually is very good for you at removing all that toxic stuff. What watermelon does is it basically clears everything because it is mostly water.”

But do dietitians agree with Butler? Here's an in-depth look at the diet, along with what they had to say.

What Is the Watermelon Diet?

Different versions of the watermelon diet have been making their way around the internet. At its core, the diet involves eating nothing but watermelon for a set time period. Common variations run from three to seven days, and after that, you add in some or all of the foods you normally eat, with or without watermelon. Since watermelon is a low-calorie food — one cup of diced watermelon has about 46 calories, according to the U.S. Department of Agriculture (USDA) — this diet is very low in calories. It’s considered a cleanse or detox diet.

YouTubers who try it brag about losing lots of weight — 13 pounds in seven days, for example, and say they stop craving junk food, clear their skin, have more mental clarity and energy, and feel lighter and less bloated.

But the dietitians we spoke with aren't fans. “[Gabi Butler’s] advice about the watermelon diet is more toxic than the toxins that she's trying to get rid of with this cleanse,” says Bonnie Taub-Dix, RDN, the creator of BetterThanDieting.com and the author of?Read It Before You Eat It: Taking You From Label to Table. “It’s a shame that she doesn’t understand her importance as a role model.” Unfortunately, people like Butler who are in the public eye can influence fans to try fad diets like this one.

“I’m a huge fan of watermelon and fruit in general, but this diet is not helpful,” says Samantha Cassetty, RD, the New York City–based coauthor of Sugar Shock. “Watermelon happens to be a very healthy food, but there's no evidence that eating it exclusively is a healthy thing to do. In fact, it's the opposite.”

Both Cassetty and Taub-Dix are skeptical of cleanses in general. “There’s no scientific validity to doing a cleanse,” Cassetty says. “The idea that you could eliminate toxins by just eating watermelon is totally untrue.”

Taub-Dix points out that you don’t need a restrictive diet to cleanse your body — your liver and kidneys do that for you.

Common Questions & Answers

Can you lose weight by eating only watermelon?
Yes. Very low calorie diets like the watermelon diet can lead to weight loss. But this diet isn’t sustainable, and you’re likely to regain the weight when you add other foods back into your diet.
Does watermelon help you lose belly fat?
No. No one food makes belly fat disappear. Losing belly fat and losing weight are complicated and involve a series of behavior changes.
Is the watermelon diet safe?
Our dietitians don’t recommend the watermelon diet for anyone, but it’s especially risky for people who have a history of disordered eating, have type 1 or type 2 diabetes, are pregnant or breastfeeding, or are under age 18 or over age 65.
How long do you do the watermelon diet?
Timeframes vary. There are a few versions of the watermelon diet, and people follow the “watermelon only” phase of the diet for three to seven or more days.
Is a watermelon cleanse healthy?
No. Eating excessive fruit can make you feel lousy — it can lead to gas, bloating, and diarrhea. And if you exercise when you’re taking in so few calories and nutrients you may feel dizzy, tired, or weak, and you could pass out.

How Does the Watermelon Diet Work?

On the watermelon diet, you eat nothing but watermelon for a certain number of days. Some versions don’t have guidelines on how much watermelon you eat. Others recommend a certain amount.

After your days of eating nothing but watermelon end, some versions add light meals accompanied by lots of — you guessed it — watermelon. For others, you revert back to your typical diet. You might choose to repeat the watermelon diet anytime you feel the need for a cleanse or detox.

Proposed Benefits of the Watermelon Diet

On balance, watermelon is a healthy food. Research shows that watermelon is more than 90 percent water, so it’s a good source of hydration, and foods with a high water content may be more satiating, according to one small study of 24 lean women. The fruit doesn’t have any fat or cholesterol and has only a trace amount of sodium, according to the USDA. Watermelon contains:

And if you choose to eat watermelon seeds, the USDA reports that an ounce of them contains 8 grams (g) of protein and 13 g of fat.

So, no one is questioning the fact that watermelon is a healthy. But when you make it your only source of food, experts say you’re missing out on the health benefits of a host of other nutrients. “It is unhealthy to make any one food your way of life,” Cassetty says. “A healthy diet includes a range of foods.”

Can You Lose Weight on the Watermelon Diet?

Anytime you drastically restrict calories, you’re likely to lose weight. The real question should be: Is the watermelon diet a safe and effective way to lose weight? “This diet doesn’t teach you any skills that connect to weight loss,” Cassetty says. Once you stop the cleanse, “You are likely to regain that weight and potentially more, which isn’t helpful.”

Cassetty recognizes that cleanses can be appealing: “If you've been eating unhealthily for a while, you might feel like you need to do a 180, and small changes aren't top of mind. I do understand that desire. I would still discourage it, but I think people are entitled to make their own decisions about their health.”

She questions whether using the watermelon diet to lose weight could be a sign of underlying problems: “If you are willing to go to this extreme to lose weight, it could be a sign that you have an unhealthy relationship with your body or with food.”

What Are the Risks of the Watermelon Diet?

If you’re thinking about trying the watermelon diet, there are a few risks to consider. First, you may be hungry, and hunger can lead to headaches, make you irritable, and make it hard to concentrate. “Constantly overriding your body’s signals of hunger is not a respectful way to treat yourself,” Cassetty says. Eating nothing but watermelon can also produce gas, bloating, and diarrhea.

If you exercise when you’re not taking in many calories or nutrients, you could become dizzy, tired, or weak. And following the watermelon diet for a prolonged time might lead to loss of muscle tissue.

The watermelon diet doesn’t teach you anything about building sustainable habits that will serve your physical and mental health in the long run. “It is unhealthy to make any one food your way of life. A healthy diet includes a range of foods,” Cassetty said.

And, if you’re intrigued by the idea of the watermelon as a cleanse, it’s not going to give you the desired effect. “The idea that you could eliminate toxins by just eating watermelon exclusively is totally untrue,” Cassetty said. “There’s no validity to any type of cleanse.”

Summary

The watermelon diet, a trendy cleanse diet, may lead to short-term weight loss. And while watermelon can be part of a healthy diet, eating it exclusively for days isn’t healthy, dietitians say. “Enjoy watermelon before, after, or during your meals, not instead of them,” Taub-Dix said.

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