Watermelon contains about 4%-7% sugar, mainly glucose, sucrose and fructose. Watermelon has a glycemic index (GI value) of 72, which is a fruit with a moderate to high GI value.
When high GI food enters the gastrointestinal tract, it is manifested as fast digestion and thorough absorption, resulting in rapid entry of glucose into the blood, which in turn causes blood sugar to rise. The recommended amount of watermelon for diabetics is about 2 taels.