How many lychees are safe to eat in a day? What TCM says about the fruit

Trees across Hong Kong and mainland China’s south are bursting with fragrant, golf-ball-sized red fruit, which can mean only one thing – lychee season is here. Lychees are much loved in the country. One well-known historical titbit tells of how Yang Guifei (719-756), the favourite concubine of Tang dynasty Emperor Xuanzong, had such a fondness for the fruit that the emperor set up a high-speed horse relay across half of China to deliver them to her at the imperial court in Chang’an while they were still fresh and juicy.

While for many the fruit is a seasonal favourite – roughly from late May to early July – traditional Chinese medicine (TCM) practitioners urge people to enjoy it in moderation. In TCM, lychees are classified as “warm” or “heaty” – a concept known as yit hei (“hot air” – also written yeet hay) in Cantonese that describes a build-up of heat in the body.

According to Karen Cheung, a registered TCM practitioner at Ayla Executive Medical in Hong Kong, eating too many can disrupt the body’s natural balance, leading to inflammatory symptoms. Excess consumption can trigger sore throats, mouth ulcers, acne breakouts, constipation and eczema flare-ups. In moderation, lychees offer distinct benefits. Cinci Leung, a registered TCM practitioner and founder of wellness platform CheckCheckCin, notes that the fruit is excellent for individuals prone to “coldness” (a depletion of the body’s warming energy known as yang), or “paleness” (an inability to generate and circulate blood and vital energy, known as qi).

It can also be good for those recovering from illness. Cheung adds that the fruit helps tonify the blood, promote qi circulation and support digestion. Deadly delicious? The risks associated with eating too many are amplified on an empty stomach, a warning backed by both TCM tradition and modern medical science.

A high-profile investigation into the 2013 and 2014 tragic deaths of children in northern India, in a region known as the country’s “lychee capital”, linked the fatalities to methylene cyclopropyl-glycine (MCPG), a natural toxin found in the fruit. A subsequent 2020 research paper noted that MCPG interferes with the body’s ability to produce glucose, triggering severe hypoglycaemia – low blood sugar – in children who had eaten little else. Signs that blood sugar levels are too low may include looking pale, shakiness, sweating, headache, hunger or nausea, an irregular or fast heartbeat, fatigue, dizziness or lightheadedness, and tingling or numbness in the lips, tongue or cheeks. Pesticide exposure was also found to be a compounding factor.

After the local government began public awareness campaigns warning parents never to let children eat lychees on an empty stomach, this problem has largely been resolved. The underlying takeaway for lychee eaters everywhere is to never gorge on lychees when fasting. For the average consumer, lychees are perfectly safe in moderation. Leung recommends a daily limit of 10 to 15 lychees for adults and five to 10 for children.

To enjoy the fruit without overloading your system with “heat”, Cheung has a few suggestions: Peel the lychees and soak them in mild salt water before eating. Enjoy them with “cooling” foods such as watermelon, pear, star fruit, mung bean soup, and chrysanthemum or winter melon teas. If you are already battling mouth ulcers or acne breakouts, avoid pairing your lychee feast with spicy foods or curries. Nutritious lychee facts Fresh lychees have a higher concentration of vitamin C than oranges and strawberries: just nine of them contain 100 per cent of an adult’s daily recommended vitamin C intake.

There are about 66 calories in 100 grams of the fruit – about seven to 10 lychees. Lychees stop ripening after they are picked from the tree. Choose red fruit over green fruit, as green fruit tends to be less sweet and may contain more MCPG. Wrap unpeeled lychees in a paper towel inside a perforated plastic bag in the fridge to keep them fresh for up to a week.

At room temperature, the shells will turn brown within days. Like what you read? Follow SCMP Lifestyle on Facebook, X and Instagram. You can also sign up for our eNewsletter here.