Everything You Need to Know About the Watermelon Diet

Low in calories, watermelon makes a nutritious snack for dieters.
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With only 46 calories per serving, watermelon makes a perfect snack between meals. It's nutritious and refreshing, providing both flavor and health benefits. Plus, it fills you up quickly and curbs sugar cravings.


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The watermelon fast diet, though, won't necessarily help you shed pounds. In fact, this weight-loss diet can be harmful to your health and often results in weight regain.


The diet plan requires eating nothing but watermelon for up to 10 days at a time. But this — or any diet — that encourages you to only eat a single food can be dangerous because it doesn't provide enough calories or nutrition, per the National Center for Complementary and Integrative Health.

What Is the Watermelon Fast Diet?

The watermelon diet is promoted as a detox plan that cleanses your body and aids in weight loss. Its proponents claim that it helps flush out toxins, improves your energy levels and wards off infections.


Those benefits sound good, don't they? There's a catch, though. Watermelon fast guidelines stipulate that you must eat nothing but the melon for five, seven or sometimes even 10 days at a time. That's rule number one.

The second rule says that dieters must eat 1 kilogram of watermelon for every 10 kilograms of body weight. Some versions include two or more phases to supposedly help you keep the pounds off.


Does the Watermelon Fast Work for Weight Loss?

Just like the pineapple diet or the cantaloupe diet, this slimming plan is low in calories and lacks variety. Put simply, it's a crash diet that limits your food choices and can take a toll on your health.


While watermelon fasting may promote weight loss in the short term due to dangerous calorie restriction, this is only temporary. According to the Cleveland Clinic, rapid weight loss causes your metabolism to slow down, making it harder for your body to burn calories and encouraging weight regain.

What's more, shedding pounds too fast means you're burning muscle mass instead of fat, which likewise decreases your body's long-term strength and calorie-burning ability. In other words, you'll gain back any weight you lose on the watermelon fast diet at the expense of your wellbeing.

Fast weight loss — like what the watermelon fast diet promises — can also harm your health by causing the following problems:

  • Digestive problems like constipation
  • Fatigue and loss of energy
  • Loss of bone density and strength
  • Decreased immune function
  • Hair loss

And those aren't the only risks — according to a small 2018 study in the European Society of Cardiology, crash diets may may affect cardiovascular function and worsen existing heart problems. People who followed a diet providing only 600 to 800 calories per day experienced a 44 percent increase in heart fat levels after just one week.

The takeaway: Do not try the watermelon fast diet for any reason. Not only will it not help you lose weight in the long term, but it could damage your health.


If weight loss is your goal, talk to your doctor about the safest way to shed pounds.

Watermelon Benefits and Nutrition Facts

If your love for watermelon is what attracted you to the fasting plan in the first place, luckily, the fruit still has its place in a safe, balanced diet. Per the USDA, the nutritional content of a 1-cup serving includes:

  • 46 calories
  • 1 g protein
  • 12 g carbs
  • 0.2 g fat
  • 0.6 g fiber
  • 9 g sugar

Plus, it's rich in vitamins and is also a good source of l-arginine, l-citrulline and various antioxidants that may help decrease post-exercise inflammation and boost immune function, according to a 2016 review in Nutrients.

Watermelon may benefit your heart, too. A July 2014 study in the American Journal of Hypertension found that this fruit may reduce cardiac stress and aortic blood pressure in adults with obesity. Lycopene, one of the most abundant antioxidants in watermelon, may also lower your risk of diabetes and heart disease, per June 2014 research in Europe PMC.

How Much of the Weight of Watermelon Is Water?

About 90 percent, per the USDA, which is why the fruit is so low in calories and also able to fill you up.

Alternatives to Watermelon Fasting

Instead of following a crash diet, making tweaks to your lifestyle is the best way to lose weight safely and sustainably. According to the Mayo Clinic, this means losing weight at the expert-recommended pace of 1 to 2 pounds per week through a combination of eating a balanced diet and exercising regularly.

A nutritious diet generally includes the following foods:

  • Fruit
  • Vegetables
  • Legumes like lentils, peas and beans
  • Whole grains like spelt, buckwheat and oatmeal
  • Beneficial fats like avocados, seeds and olive oil
  • Lean proteins like fish, poultry and nuts

In terms of exercise, the Physical Activity Guidelines for Americans recommend adults get 150 to 300 minutes of moderate-intensity cardio exercise per week, plus two strength training sessions.

Try These Nutritious Recipes With Watermelon