My grandmother said the same thing about wet hair, not wearing socks making you sick.
My grandparents were full of "wisdom":
"If you pull that hair, two will grow back".
After a meal, you should have a strong cup of tea because "strong tea cuts the grease". Uuuuuh why not lay off the greasy food for a change?
If you leave uneaten rice in your bowl, you will have a spotty complexion.