Accused of being “too sugary” and spiking blood sugar levels, watermelon has finally got its revenge: thanks to its exceptional water content and high satiating power, it hydrates and satisfies the palate with a truly negligible calorie intake. Dr. Simone Gabrielli explains everything.
The most wonderful season of the year, summer, arrives, and with it, the usual beach dilemma: can you eat watermelon if you’re on a diet? Despite being the quintessential thirst-quenching and hydrating fruit, it periodically ends up in the dock for being “too sugary” and therefore harmful to your figure. The issue stems from a fact that is true, but misinterpreted: watermelon has a high glycemic index, meaning that the sugars it contains enter the bloodstream quickly.
Is this really the case, or is it yet another false myth about our beloved fruit? “This parameter, taken alone, is misleading,” explains Simone Gabrielli, biologist and nutritionist. “What determines the body’s insulin response is the glycemic load, or the actual quantity of carbohydrates present in the portion consumed.”
So, the glycemic index measures how quickly a food raises blood sugar, but it doesn’t take into account the quantity actually consumed, nor whether we eat this, or other fruits, within a meal or snack, perhaps after vegetables, proteins and fats, macronutrients that naturally modulate the absorption of sugars.
Because watermelon is made almost entirely of water, the amount of sugar per slice is actually very low (about 3-4 grams per 100 grams in the form of fructose). Consequently, the actual impact on blood sugar levels is minimal and does not pose a problem for healthy, normal-weight individuals. Furthermore, when we consume fresh fruit, we also consume fiber, vitamins, and minerals, micronutrients that work synergistically with sugars to help maintain blood sugar levels. Banning it from your diet is a colossal mistake.
How Many Calories Are in Watermelon?
Nutritionally, watermelon is one of the lowest-calorie fruits in existence: it provides just 16 calories per 100 grams of pulp. A treasure trove of valuable micronutrients, it can be considered a true natural supplement , ideal for dealing with the seasonal heat.
Water, which makes up over 92 percent of its total weight, is the most abundant element. Ideal for replenishing fluids lost through sweating and stimulating diuresis, it is a “hydration bomb”;
Minerals and vitamins: potassium is the predominant mineral, essential for nerve transmission, fluid balance, and valuable for counteracting muscle cramps, fatigue, or drops in blood pressure due to heat. It is also rich in vitamin C, vitamin A, and beta-carotene, useful for cell turnover and maintaining healthy epithelial tissue;
Fiber: It is contained in modest percentages (about 0.2-0.4 grams), which makes the pulp extremely light and easy to digest (as long as it is not eaten frozen after a heavy meal). The seeds also have mild laxative properties, excellent for constipation.
Antioxidants: among these, lycopene stands out, the pigment responsible for the red color of the pulp, with exceptional anti-inflammatory and antioxidant properties. It also contains citrulline, an amino acid precursor to arginine, essential for stimulating nitric oxide, promoting vasodilation and supporting cardiovascular function.
How Much Watermelon Can You Eat on a Diet?
If you’re following a low-calorie diet or simply want to maintain your weight, watermelon is an excellent ally. Composed almost entirely of water, it promotes deep hydration, acts as a natural diuretic, and combats water retention by promoting the elimination of excess fluids. The standard portion recommended by nutritional guidelines is about 150 grams (the weight refers to the pulp only, without the rind and seeds).
However, given its very low calorie content (and irresistible goodness), if you decide to treat yourself to it as an afternoon snack, you can easily eat up to a 200-300 gram slice: it will leave you feeling very full and satisfying despite its very few calories. “The smart tip is to avoid overindulging in it at the end of a meal to avoid slowing down digestion or bloating,” suggests Gabrielli.
If we then wanted to transform it into a natural supplement, very useful on hot days or after an intense training session, we suggest adding a few drops of lemon juice and a pinch of whole sea salt.
Although it is a virtuous food, to be consumed with complete peace of mind, watermelon must be managed carefully in specific clinical situations: if you suffer from digestive disorders or reflux, it is better to avoid it at the end of a meal, but move it to mid-morning or mid-afternoon as an isolated snack: the abundance of water can hinder the action of gastric juices and increase stomach distension, with a consequent slowing of digestion and a feeling of heaviness.
Even in cases of irritable bowel syndrome, it could cause bloating and intestinal pain, which is why it’s always best to consult a professional. What if you suffer from insulin resistance or diabetes? There’s no absolute ban, but portions and meal placement must be carefully considered to avoid exceeding the overall glycemic load established by your treatment plan. It’s best to consume a smaller portion, including it as a dessert after a full meal that includes fiber, protein, and fat.
Does Watermelon Help You Lose Weight?
The answer, obviously, is no. There are no foods that have the intrinsic power to make you lose weight: what really matters is your lifestyle and your overall diet. “Real weight loss is achieved only when you establish a calorie deficit, that is, when you consume fewer calories than you burn throughout the day,” the expert states.
While there are no foods that make you lose weight, we can confidently say that watermelon is undoubtedly a valuable ally on a weight-loss journey. Thanks to its exceptional water content and high satiating power, it fills the stomach and curbs hunger despite its negligible caloric intake. Replacing a packaged snack, a bar, or a pack of crackers with a nice slice of fresh watermelon is definitely a winning move.
Furthermore, its exceptional versatility allows us to experiment in the kitchen and make meals or snacks even more delicious and satisfying: in addition to being enjoyed plain, fresh, but not cold from the fridge, it can be cut into cubes and used to create colorful fruit salads or original skewers; it can be used to make flavored waters, a great ally on hot days, thirst-quenching smoothies, and homemade ice creams without added sugar. Those who like to be daring can even include it in savory dishes: it is surprising when paired with cheeses like feta or goat cheese, balancing their saltiness, but also with cured meats, white meats, and raw fish carpaccio.
Try it blended with tomatoes, cucumbers, and a few basil leaves: you’ll get a fresh gazpacho to serve as an aperitif or to sip before a home-cooked dinner to “cheat” your appetite a little and not arrive too hungry.