It’s one of summer’s simplest pleasures: watermelon, with its bright red flesh, thirst-quenching texture, and the promise of freshness. We love it sliced, diced, or even blended into a smoothie. However, behind its “healthy” appearance lies a lesser-known effect on our bodies, particularly on blood sugar levels.
A false friend of blood sugar?
Long considered a weight-loss ally thanks to its high water content and low calorie count, watermelon is making a strong comeback on every table as soon as the temperature rises. But recent studies warn: this sweet, innocent-tasting fruit can cause rapid increases in blood sugar levels, sometimes more pronounced than those caused by white sugar itself.
Why? Because it contains very little fiber and almost no fat or protein, elements that usually slow the absorption of sugars. The result: once in the mouth, its sugars (glucose + fructose) are absorbed rapidly, causing a rapid metabolic spike, especially in people over 50 or those with insulin sensitivity.
A surprising glycemic index.
The glycemic index (GI) of watermelon ranges from 72 to 80, depending on the variety, placing it among the high-GI fruits. For comparison: an apple has a GI of 38, a strawberry 41, and white sugar around 65.
What does this mean? A 150g serving of watermelon consumed on an empty stomach can cause a greater increase in blood sugar levels than 50g of pure sugar. And a rapid spike also leads to a sudden drop, resulting in fatigue, hunger pangs, and sugar cravings… the famous “yo-yo effect” we could do without.
How to enjoy it without ruining your blood sugar
- Watermelon isn’t your enemy. But like all foods high in fast-acting sugars, it requires some strategy. Here’s how to include it in your diet without affecting your glucose levels:
Avoid eating it on an empty stomach: an empty stomach accentuates the “quick release” effect.
Pair it with a source of protein or healthy fats: plain yogurt, a few almonds, a spoonful of ricotta.
Maintain moderate consumption: 100-150 g is more than enough to refresh without overdoing it.
Choose watermelon at the end of a meal, not as a stand-alone snack.
Alternate it with low-glycemic index fruits: kiwi, apple, raspberry, orange, etc. for a gentler alternative.
Key tips
Watermelon isn’t a food to be banned, far from it! But it deserves to be consumed in moderation and with caution, especially if you’re monitoring your blood sugar or if you experience a drop in energy after meals. Because yes, a fruit can be hydrating and at the same time cause a roller coaster effect on your body.