The Watermelon Diet: The Juicy Summer Reset Almost Nobody Talks About

Picture this: it's the height of summer, watermelons are stacked high and cheap at every market stall, and somewhere between the beach and the barbecue, you start wondering whether this giant, dripping fruit could actually help you slim down. It turns out you're not the only one who has wondered that — the idea has quietly built a loyal following of people who swear by it every July and August.

The trend even reached mainstream television. Netflix cheerleading star Gabi Butler mentioned on the docu-series "Cheer" that she had eaten only watermelon for three days as a way to feel lighter before resuming her normal routine — a small, personal anecdote that's part of why the watermelon diet keeps resurfacing online every summer.

Why Watermelon Earns Its Reputation

Watermelon isn't just cheap, sweet, and refreshing — it's genuinely interesting from a nutritional standpoint. A 2025 narrative review published in the journal Nutrients on watermelon's L-citrulline content confirms that the fruit contains around 30–46 kcal per 100 grams and is unusually rich in L-citrulline, an amino acid the body converts into L-arginine to support healthy blood vessel function.

That same citrulline content is also behind watermelon's well-known diuretic effect, which we've covered before as one of the reasons watermelon is an ideal food for hot summer days. A recent laboratory study on watermelon rind extract and its diuretic and metabolic effects found that citrulline- and potassium-rich watermelon compounds were linked to reduced body weight and fat mass in animal models — an early but promising signal for why the fruit has such a strong "cleansing" reputation.

Beyond the flesh, don't overlook the seeds. According to the Cleveland Clinic's rundown of watermelon's nutrition benefits, the seeds are a genuinely good source of magnesium, folate, and heart-friendly fatty acids, so roasting and snacking on them instead of tossing them out is worth considering.

Nutritionists also point to watermelon's natural sweetness as a useful ally against the urge for something sugary — a chocolate bar or a scoop of ice cream — since it delivers a satisfying dose of sweetness for very few calories. If sugar cravings are a recurring struggle for you, it's worth reading our piece on the everyday foods that quietly sabotage a diet by feeding sugar cravings.

The Two Versions of the Watermelon Diet

Now that watermelon season is in full swing and prices are at their lowest, this is the natural moment of year when people consider trying it. There are two common approaches: a short 3-day version, and a longer, more gradual 13-day plan.

The Short, 3-Day Reset

The short version is simple: for three days, watermelon is the only food on the menu. The idea is to give digestion a break and let the body lean on stored energy rather than new food coming in. Some people report losing a noticeable amount of weight over the three days, though it's worth being realistic about where that number comes from.

According to Healthline's review of the evidence behind the watermelon diet, there is very limited research backing specific weight-loss claims, and most people who try mono-fruit diets like this one are mainly losing water weight rather than body fat — weight that tends to come back once regular eating resumes. Dr. Mark Hyman, a physician who commented on the trend for Fox News, put it plainly: turning any single fruit into the centerpiece of a restrictive diet "can actually backfire" on long-term health, since it leaves out protein and healthy fats the body needs.

During the three days, stick to water, and unsweetened black coffee if you can't skip your morning cup. Skip fruit juices and alcohol entirely — they add sugar and calories that work against the point of the reset. Because it's so restrictive, most nutrition-minded sources agree this kind of cleanse shouldn't be repeated more than twice a month, and it's a good idea to check with a doctor first if you're pregnant, have diabetes, kidney issues, or any other ongoing health condition.

The Longer, 13-Day Plan

The extended version starts the same way — three watermelon-only cleansing days — but then eases back into a more balanced way of eating over a five-day meal rotation, repeated twice (for ten days total), which can be extended further if it's working well for you.

• Day 1
  
  Breakfast: watermelon + coffee
  
  Lunch: 150 g boiled lean beef + 150 g rice + watermelon
  
  Dinner: 100 g cottage cheese + a slice of whole-grain bread + watermelon


• Day 2
  
  Breakfast: watermelon + coffee
  
  Lunch: 100 g boiled chicken + a slice of bread + watermelon
  
  Dinner: 100 g grilled fish + 100 g rice + watermelon


• Day 3
  
  Breakfast: watermelon + a slice of bread + coffee
  
  Lunch: 50 g pasta with a simple tomato sauce + watermelon
  
  Dinner: a light salad (oil and vinegar only) + watermelon


• Day 4
  
  Breakfast: watermelon + coffee
  
  Lunch: broccoli soup + a slice of whole-grain bread + watermelon
  
  Dinner: 3 small baked potatoes + watermelon


• Day 5
  
  Breakfast: watermelon + coffee
  
  Lunch: 150 g boiled beef + a slice of whole-grain bread + watermelon
  
  Dinner: 100 g cottage cheese + a slice of whole-grain bread + watermelon

Cottage cheese shows up a few times in that plan for good reason — it's a lean protein that helps balance out watermelon's very low protein content, something we also touch on in our piece on pairing fruit with cottage cheese or yogurt for a more balanced snack. Throughout the whole plan, watermelon itself can be eaten freely between meals whenever hunger strikes.

A Few Honest Words of Caution

None of this is medical advice, and a watermelon-heavy diet is not a substitute for a varied, balanced way of eating over the long run. The National Institutes of Health has noted, in guidance summarized by nutrition experts, that short "detox" or cleanse-style diets like this one can bring on digestive discomfort, fatigue, or light-headedness in some people, precisely because they're so low in protein, fat, and overall calories.

If you want to try it, treat it as an occasional, short-lived reset rather than a long-term strategy — and if you have any underlying health condition, are pregnant or breastfeeding, or take regular medication, it's worth a quick conversation with your doctor or a registered dietitian first. Used sensibly and sparingly, though, a few watermelon-forward days in the height of summer are a genuinely enjoyable, low-cost way to eat lighter, stay hydrated, and maybe even take the edge off a sweet tooth.