I eat Lychees too, and love them. Until I read this article, I was unaware of their bgl lowering properties, and I have not seen them being suggested as an alternative therapy anywhere. However, it may now crop up, but without the cautionary tale to temper one's enthusiasm, so this is why I posted this possible post-truth article.
I cannot say I have researched this myself, so cannot provide any other source backup for this article, so it may be faux. But the BBC normally check their info quite well.