Sweet longans are low-GI, but moderation is key for diabetics, says nutritionist

Many people avoid longans due to their perceived sweetness, fearing they will cause a rapid increase in blood sugar. However, nutritionist Xue Xiaojing clarifies that sweetness does not directly correlate with a fruit's glycemic impact. Recent studies indicate that longans have a GI of approximately 44.5, classifying them as a low-GI fruit.

Xue explained that the glycemic index measures how quickly a food raises blood sugar levels after consuming a standardized amount of digestible carbohydrates. Factors such as sugar types, water content, fiber, fruit structure, and other plant compounds influence this response. Therefore, even though longans taste sweet, they do not necessarily lead to a sharp spike in blood glucose.

While longans are classified as low-GI, Xue cautions against unlimited consumption. A 100-gram serving of longans contains about 18 grams of carbohydrates and 15.2 grams of sugar. Consuming 200 grams could lead to nearly 30 grams of sugar, significantly increasing the overall glycemic load. For individuals managing diabetes or pre-diabetes, it is recommended to consume about 13 longans per serving as a reference point, adjusting based on personal blood sugar responses and guidance from a healthcare team.

Longans do provide nutritional benefits, including vitamin C. A 100-gram serving contains about 95.4 milligrams of vitamin C, which is essential for collagen synthesis, antioxidant functions, and immune support. However, Xue noted that fruits like red guava are significantly richer in vitamin C, offering over 214.4 milligrams per 100 grams. Thus, while longans can be part of a healthy diet, they should be consumed mindfully, considering portion sizes and individual health needs.