Houdingnuo can cause nausea and vomiting, and it is required to take it on an empty stomach for 2 hours before and after. If you don't spit it out, eating it won't affect the efficacy.
By the way, the morning-after pill has a great influence on women's health, and it is easy to cause endocrine disorders and pigmentation. Try to eat less. It is recommended to take it at least every two months, preferably at least half a year.