Does eating watermelon raise or lower blood sugar?

Generally speaking, eating watermelon tends to raise blood glucose levels.

Although watermelon contains relatively low amounts of sugar, it has a high glycemic index (GI). For healthy individuals, moderate consumption of watermelon typically does not cause a significant rise in blood glucose, as their normal insulin secretion effectively counteracts any glucose elevation and maintains blood glucose within the normal range. However, people with diabetes should generally avoid consuming large quantities of watermelon. Due to reduced insulin secretion in diabetic patients, blood glucose regulation is impaired; excessive watermelon intake may therefore trigger a sudden spike in blood glucose, posing risks to health and life. That said, diabetic patients may still consume small, controlled portions of watermelon. Watermelon contains various nutrients—including protein, glucose, fructose, sucrose, and multiple vitamins—which supply energy and essential nutrients to the body. As long as blood glucose levels are well-controlled within a safe range, diabetic patients may occasionally enjoy modest servings of watermelon.

Individuals with diabetes should carefully manage their daily diet—opting for smaller, more frequent meals—and minimize intake of foods high in sugar.