Longan (Dimocarpus longan) – small round Asian tropical fruit; called “dragon eye” because peeled fruit looks like an eye with white flesh and dark seed; native to southern China and tropical Asia; widely grown in Vietnam, Thailand, Taiwan, southern China, Florida (limited). Related to lychee and rambutan (Sapindaceae family). Distinctive features – smooth tan-brown shell; translucent white sweet juicy flesh; large dark inedible seed in center; sweeter and less acidic than lychee; honey-like flavor. Per ½ cup (~75 g) – 50 calories, 13 g carbohydrate, 1 g fiber (net 12 g), 1 g protein, 0 g fat. Per 1 cup – 100 calories, 26 g carb. Per individual fruit (~10 g) – 7 calories, 2 g carb. Glycemic index estimated 50-60 (moderate). Benefits – vitamin C (40-80% DV per cup depending on freshness), copper, B vitamins (riboflavin); some traditional Chinese medicine use; antioxidants. Concerns – low fiber (only 1 g per cup) compared to other tropical fruits; concentrated natural sugars; canned in heavy syrup adds significant sugar; dried very concentrated; seeds inedible. Same family with subtle differences as lychee and rambutan. All three are Sapindaceae family. Differences – longan (smooth tan shell; smaller; honey-sweet; less juicy than lychee); lychee (bumpy pink-red shell; more aromatic; juicier; tart-sweet); rambutan (hairy red/yellow shell; sweeter; smaller). Nutrition similar across three – per cup all around 100-125 cal, 26-32 g carb, 1 g fiber, low GI. For diabetes – all suitable in moderate portions (½ cup). Longan most affordable and widely available canned/dried. Fresh moderate portions for diabetes – 5-7 fruits (about ½ cup flesh = 12 g carb) as snack; pair with handful of nuts for satiety; mixed Asian fruit salad with smaller portion; topping for plain Greek yogurt; smoothie with protein powder, almond milk, ½ cup longan; sparkling water with longan and lime (mocktail); Asian-inspired salad addition; pair with cheese (sweet-savory). Forms to limit/avoid – canned longan in heavy syrup (typical 1 cup = 35 g carb); dried longan very concentrated (½ cup dried = 70 g carb!); longan sweet soup (tong sui); longan honey; longan ice cream/jelly. Longan has cultural significance in Chinese culture – cultivated 2000+ years; dried longan (“guiyuan”) in TCM for fatigue, insomnia, anemia; used in herbal soups and teas.
Longan Nutrition
| Portion | Calories | Carbs (g) | Fiber (g) |
|---|---|---|---|
| 1 fruit (~10 g) | 7 | 2 | 0.1 |
| 5-7 fruits (½ cup, ~75 g) | 50 | 13 | 1 |
| 1 cup (~150 g) | 100 | 26 | 2 |
| Canned in syrup (1 cup) | 185 | 45 | 1 |
| Dried longan (¼ cup, 30 g) | 100 | 26 | 1 |
| Longan honey (1 tbsp) | 65 | 17 | 0 |
Sapindaceae Family Comparison
| Fruit | Shell | Flesh | Flavor |
|---|---|---|---|
| Longan | Smooth tan-brown | White translucent | Honey-sweet, less acidic |
| Lychee | Bumpy pink-red | White translucent | Sweet-tart, aromatic |
| Rambutan | Hairy red/yellow | White translucent | Sweet, less acidic than lychee |
| Pulasan | Spiked rind | Similar to rambutan | Very sweet |
Diabetes-Friendly Applications
- Fresh longan (5-7 fruits, ½ cup) as snack.
- Pair with handful of nuts.
- Mixed Asian fruit salad (small portions).
- Topping for plain Greek yogurt.
- Smoothie with protein, almond milk, ½ cup longan.
- Mocktail with sparkling water and lime.
- Salad addition with chicken/shrimp.
- Pair with cheese (sweet-savory).
- Frozen for smoothies.
- Garnish for Asian-inspired dishes.
- Small dried portion (1 tbsp) in herbal tea.
Things to Limit
- Canned longan in heavy syrup.
- Dried longan large portions.
- Longan sweet soup (tong sui).
- Longan honey.
- Longan ice cream/jelly.
- Sweetened longan tea.
Chinese Cultural Significance
- Cultivated 2000+ years in China.
- Traditional Chinese medicine (TCM) use.
- Dried longan (“guiyuan”) – warming, nourishing.
- Used for fatigue, insomnia, anemia in TCM.
- Longan and red date tea (traditional).
- Longan sweet soup (tong sui) dessert.
- Longan in herbal chicken soup.
- Eight treasure congee (ba bao zhou) ingredient.
- Some preliminary research on antidiabetic effects.
Where to Find Longan
- Asian markets (most reliable).
- Some Whole Foods (frozen).
- Online retailers.
- Some specialty markets in season.
- Fresh available summer-fall (July-October).
- Frozen and canned year-round.
- Dried at Chinese herbalists or markets.
- Cost – fresh $5-12/lb in season; canned in syrup $2-4 can; dried $10-15/lb.
The Bottom Line
Longan (Dimocarpus longan) – small round Asian tropical fruit; called “dragon eye”; native to southern China and tropical Asia; widely grown in Vietnam, Thailand, Taiwan, southern China. Related to lychee and rambutan (Sapindaceae family). Distinctive features – smooth tan-brown shell; translucent white sweet juicy flesh; large dark inedible seed; sweeter and less acidic than lychee; honey-like flavor. Per ½ cup (~75 g) – 50 calories, 13 g carbohydrate, 1 g fiber (net 12 g), 1 g protein, 0 g fat. Per individual fruit – 7 calories, 2 g carb. Glycemic index estimated 50-60 (moderate). Benefits – vitamin C (40-80% DV per cup), copper, B vitamins (riboflavin); some traditional Chinese medicine use; antioxidants. Concerns – low fiber (only 1 g per cup); concentrated natural sugars; canned in heavy syrup adds significant sugar; dried very concentrated; seeds inedible. Compared to lychee and rambutan – all Sapindaceae family with similar profiles; longan most affordable and widely available canned/dried; lychee more aromatic; rambutan hairy red shell. All suitable in moderate portions (½ cup) for diabetes. Fresh moderate portions for diabetes – 5-7 fruits (½ cup flesh = 12 g carb) as snack; pair with nuts for satiety; mixed fruit salad; topping for plain Greek yogurt; smoothie with protein; mocktail with sparkling water and lime. Forms to limit – canned in heavy syrup (typical 1 cup = 35 g carb); dried longan very concentrated (½ cup = 70 g carb!); longan sweet soup; longan honey. Cultural significance – 2000+ years cultivation in China; dried longan (“guiyuan”) in TCM for fatigue, insomnia, anemia; used in herbal soups. Available at Asian markets, some Whole Foods (frozen), online retailers; fresh seasonal (July-October); frozen and canned year-round; dried at Chinese herbalists. For adults with type 2 diabetes – longan is enjoyable Asian tropical fruit in moderate portions (½ cup); pair with protein for blood sugar stability; avoid canned-in-syrup and large dried portions; cultural significance allows respectful inclusion; one of more affordable tropical fruits. See our broader diabetes diet guide for context.
